Optical assembly with cable retainer

ABSTRACT

An optical cable subassembly includes one or more optical waveguides, at least light coupling unit comprising a first attachment area permanently attached to the optical waveguides, and at least one cable retainer comprising a second attachment area permanently attached to the optical waveguides and adapted to be installed in a housing. A length of the optical waveguides between the first attachment area and the second attachment area allows a bend in the optical waveguides that provides a predetermined mating spring force at a predetermined angle of the light coupling unit when installed in the housing.

TECHNICAL FIELD

This disclosure relates generally to optical connector assemblies andmethods related to optical connector assemblies.

BACKGROUND

Optical connectors can be used for optical communications in a varietyof applications including telecommunications networks, local areanetworks, data center links, and internal links in computer devices.There is interest in extending optical communication to applicationsinside smaller consumer electronic appliances such as laptops and evencell phones. Expanded optical beams may be used in connectors for thesesystems to provide an optical connection that is less sensitive to dustand other forms of contamination and so that alignment tolerances may berelaxed. Generally, an expanded beam is a beam that is larger indiameter than the core of an associated optical waveguide (usually anoptical fiber, e.g., a multi-mode fiber for a multi-mode communicationsystem). The connector is generally considered an expanded beamconnector if there is an expanded beam at a connection point. Theexpanded beam is typically obtained by diverging a light beam from asource or optical fiber. In many cases, the diverging beam is processedby optical elements such as a lens or mirror into an expanded beam thatis approximately collimated. The expanded beam is then received byfocusing of the beam via another lens or mirror.

BRIEF SUMMARY

Some embodiments are directed to an optical cable subassembly. Thesubassembly includes one or more optical waveguides, at least one lightcoupling unit comprising a first attachment area permanently attached tothe optical waveguides, and at least one cable retainer. The cableretainer includes a second attachment area permanently attached to theoptical waveguides and adapted to be installed in a housing. A length ofthe optical waveguides between the first attachment area and the secondattachment area is configured to allow a bend in the optical waveguidesthat provides a predetermined mating spring force at a predeterminedangle of the light coupling unit when installed in the housing.

In some embodiments, an optical cable subassembly includes one or moreoptical waveguides, at least one light coupling unit permanentlyattached to and adapted to receive optical signals from the opticalwaveguides and propagate the received optical signal therein, and acable retainer permanently attached to the plurality of opticalwaveguides and adapted to engage a corresponding retainer mount in aconnector housing. When the subassembly is installed in the housing, theengagement of the cable retainer and the retainer mount provides theonly attachment of the subassembly to the housing between the cableretainer and the light coupling unit.

According to some embodiments, an optical cable subassembly include oneor more optical waveguides, at least one light coupling unit comprisinga first attachment area for receiving and permanently attaching to theplurality of optical waveguides, and at least one cable retainer. Thecable retainer includes a second attachment area for receiving andattaching to the optical waveguides. The cable retainer is dimensionedto couple with a retainer mount of a connector housing such that aposition of the second attachment area within the connector housing isfixed. The light coupling unit and the first attachment area areconfigured to move within the connector housing relative to the fixedposition of the second attachment area. A length of the opticalwaveguides between the first attachment area and the second attachmentarea allows the optical waveguides to bend within the housing as thefirst attachment area moves relative to the second attachment area.

In accordance with some embodiments, an optical cable subassemblyincludes one or more optical waveguides, at least one light couplingunit comprising a first attachment area for receiving and permanentlyattaching to the plurality of optical waveguides, and at least one cableretainer comprising a second attachment area for receiving and attachingto the plurality of optical waveguides. The cable retainer isdimensioned to couple with a retainer mount of a connector housing suchthat a position of the second attachment area within the connectorhousing is fixed. A length of the plurality of optical waveguidesbetween the first attachment area and the second attachment area of theoptical cable subassembly is greater than a straight-line distancebetween the first attachment area and the second attachment area afterthe optical cable subassembly is installed in the connector housing.

In some embodiments an optical connector housing has a mating end, anon-mating end opposite the mating end, and a passageway extendingbetween the mating end and the non-mating end. The passageway isdimensioned to receive an optical cable subassembly including one ormore optical waveguides attached to at least one light coupling unit andto at least one cable retainer. A retainer mount is configured toreceive the cable retainer in the housing such that the position of theoptical cable subassembly is fixed within the housing by the retainermount. The passageway is dimensioned to constrain the optical waveguidesto bend within the housing between the retainer mount and the matingend.

According to some embodiments, an optical connector assembly comprisesan optical cable subassembly and a housing. The optical cablesubassembly includes one or more optical waveguides, at least one lightcoupling unit comprising a first attachment area for receiving andpermanently attaching to the optical waveguides, and at least one cableretainer comprising a second attachment area for receiving and attachingto the optical waveguides. The housing includes at least one passagewaydimensioned to receive the optical cable subassembly and at least oneretainer mount. The at least one retainer mount is configured to couplewith the cable retainer such that a position of second attachment areais fixed within the housing. The passageway is dimensioned to constrainthe optical waveguides to bend within the housing between the firstattachment area and the second attachment area.

Some embodiments are directed to method of making an optical cablesubassembly. One or more optical waveguides are attached at a firstattachment area of a light coupling unit. the first attachment area isconfigured for receiving and permanently attaching to the opticalwaveguides. The optical waveguides are attached to a cable retainercomprising a second attachment area for receiving and attaching to theoptical waveguides. A length of the optical waveguides between the firstattachment area and the second attachment area allows a bend in theoptical waveguides that provides a predetermined mating spring force ata predetermined angle of the light coupling unit.

Some embodiments a method of making an optical connector assembly. Anoptical cable subassembly is assembled by attaching one or more opticalwaveguides at a first attachment area of a light coupling unit andattaching the optical waveguides at a second attachment area of a cableretainer. The optical cable subassembly is inserted into a housing. Thecable retainer is coupled to a retainer mount in the housing, thecoupling of the cable retainer into the retainer mount fixing a positionof the optical cable assembly within the housing. The optical waveguidesare inserted into a passageway in the housing, the passagewaydimensioned to constrain the optical waveguides to bend within thehousing between the first attachment area and the second attachmentarea.

Some embodiments are directed to a method of making an optical connectorassembly, An optical cable subassembly is assembled by: attaching one ormore optical waveguides at a first attachment area of a light couplingunit; attaching the optical waveguides at a second attachment area of acable retainer; and inserting the optical cable subassembly into ahousing. Inserting the optical cable subassembly into the housinginvolves coupling the cable retainer to a retainer mount in the housing,the coupling of the retainer and the retainer mount fixing a position ofthe optical cable assembly within the housing; and inserting the opticalwaveguides into a passageway within the housing. A length of the opticalwaveguides between the first attachment area and the second attachmentarea is greater than a distance between the first attachment area andthe second attachment area after the optical cable subassembly isinstalled in the connector housing.

According to some embodiments, an optical ferrule comprises one or moreoptical elements and one or more fiducials. Each optical element isconfigured to be on an optical path of a light ray propagating withinthe ferrule. The one or more fiducials correspond to the one or moreoptical elements.

In accordance with some embodiments, an optical ferrule is configured toreceive a one or more optical waveguides and comprises one or morefeatures, each feature corresponding to a different optical waveguideand one or more fiducials, the one or more fiducials corresponding tothe one or more features.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 shows an optical cable subassembly 100 in accordance with someembodiments;

FIGS. 2A and 2B are cutaway views of a portion of an optical cablesubassembly focusing on the light redirecting member according to someembodiments;

FIG. 3 illustrates a side view of two optical cable subassembliesshowing mated light coupling units attached to optical waveguides atlight coupling unit attachment areas in accordance with embodimentsdescribed herein;

FIGS. 4A, 4B, and 4C provide several views of portions of an opticalconnector assembly in accordance with some embodiments;

FIG. 5 depicts an embodiment of an inner housing including four opticalcable subassemblies installed in the inner housing;

FIG. 6A illustrates an inner housing having retainer mounts comprising agroup of four pegs disposed within the shared passageway in accordancewith some embodiments;

FIG. 6B illustrates the inner housing of FIG. 6A after the optical cablesubassemblies have been installed;

FIG. 7A illustrates an inner housing having retainer mounts, eachretainer mount comprising a group of two pegs disposed within a sharedpassageway in accordance with some embodiments;

FIG. 7B illustrates the position of the optical cable subassemblies inthe mated position within the inner housing of FIG. 7A;

FIG. 8A shows an example of a jig made to facilitate fabrication of anoptical cable subassembly in accordance with some embodiments;

FIG. 8B illustrates a process of making an optical connector assembly inaccordance with some embodiments;

FIGS. 9A, 9B, and 9C illustrate a lateral cross sectional view, aperspective view, and a longitudinal cross sectional view, respectively,of a cable retainer in accordance with some embodiments;

FIGS. 10A and 10B are cross sectional views that illustrate a version ofa unitary, single piece cable retainer in accordance with someembodiments;

FIG. 11A is a perspective view of an embodiment of a unitary, singlepiece cable retainer in accordance with some embodiments;

FIG. 11B shows an optical cable subassembly that includes the cableretainer of FIG. 11A;

FIG. 11C illustrates a single cable retainer attached to multipleoptical waveguides in accordance with some embodiments;

FIGS. 12, 13 and 14 illustrate cable retainers that are multi-piecestructures in accordance with various embodiments;

FIGS. 15A and 15B illustrate closed and open views of a cable retainerhaving a single piece construction with two portions that can moverelative to one another in accordance with some embodiments;

FIGS. 16A and 16B depict a retainer comprising a C-shaped collet piecein accordance with some embodiments;

FIGS. 17A, 17B, and 17C provide an example of a collet-type cableretainer in accordance with some embodiments;

FIGS. 18A and 18B illustrate a collet-type retainer comprising a colletpiece and a tapered piece in accordance with some embodiments;

FIG. 19 shows a cable retainer that includes surface features tofacilitate alignment of the individual optical waveguides in accordancewith some embodiments;

FIG. 20 depicts a cable retainer having rounded exit surfaces inaccordance with some embodiments;

FIG. 21 depicts an optical cable subassembly comprising a keyed pegcable retainer in accordance with some embodiments;

FIG. 22 and FIG. 23 depict portions of optical cable subassemblies withoptical waveguides disposed within a variable width adhesive attachmentspace of the cable retainer in accordance with some embodiments;

FIG. 24A is a cross sectional diagram of an optical cable subassemblythat includes a boot in accordance with some embodiments;

FIGS. 24B and 24C depict an optical cable subassembly including a cableretainer that is shaped so that the optical waveguides bend within thecable retainer in accordance with some embodiments;

FIG. 25 illustrates an embodiment wherein the cable retainer includes anextension that extends inside the boot in accordance with someembodiments;

FIG. 26 shows mating optical connector assemblies having male and femalecovers on the outer housings that extend over the light coupling unitsin accordance with some embodiments;

FIG. 27 provides a side view of mating hermaphroditic connectorassemblies which includes separate, removable covers in accordance withsome embodiments;

FIG. 28 provides a side view of mating hermaphroditic connectorassemblies having hinged covers in accordance with some embodiments;

FIGS. 29A and 29B depict side views of hermaphroditic connectorassemblies having spring actuated retractable covers in accordance withvarious embodiments;

FIGS. 30 and 32 illustrate various features provided on a first majorsurface of an LCU in accordance with various embodiments;

FIGS. 31 and 33 illustrate various features provided on a second majorsurface of the LCU shown in FIGS. 30 and 32;

FIGS. 34 and 36 illustrate various features provided on a first majorsurface of an LCU in accordance with various embodiments;

FIGS. 35 and 37 illustrate various features provided on a second majorsurface of the LCU shown in FIGS. 34 and 36;

FIG. 38 illustrates various features provided on a surface of an LCU inaccordance with various embodiments;

FIG. 39 illustrates various features provided on a surface of an LCU inaccordance with other embodiments;

FIG. 40A illustrates a mating interface between two LCUs that does notincorporate a particulate contaminant capture feature of the presentdisclosure;

FIG. 40B illustrates a particulate contaminant at a mating interfacebetween two LCUs that does not incorporate a particulate contaminantcapture feature of the present disclosure;

FIG. 40C illustrates particulate contaminants trapped by particulatecontaminant capture features of the present disclosure provided atmating interfaces between two LCUs;

FIG. 41 illustrates an LCU that incorporates a compound groove having acentering arrangement in accordance with various embodiments;

FIG. 42 illustrates various details of the compound groove shown in FIG.41, the groove configured to receive an optical waveguide;

FIG. 43 illustrates a longitudinal transition section of the grooveshown in FIG. 41;

FIG. 44 is a top view of an LCU attachment area comprising a forwardadhesive cavity in accordance with various embodiments;

FIG. 45 is a side view of the LCU attachment area shown in FIG. 44;

FIG. 46 is a top view of an LCU attachment area comprising lateraladhesive cavities in accordance with various embodiments;

FIG. 47 is a side view of the LCU attachment area shown in FIG. 46;

FIG. 48 is a top view of an LCU attachment area comprising a sharedforward adhesive reservoir in accordance with various embodiments;

FIGS. 49-55 illustrate a process for installing a waveguide in acompound groove of an LCU attachment area in accordance with variousembodiments;

FIG. 56 illustrates an alignment error that can occur when installing awaveguide in a compound groove;

FIG. 57 shows a groove having a recessed bottom surface and a porchregion according to various embodiments that facilitate reduction of thealignment error illustrated in FIG. 56;

FIGS. 58-60 show a groove having two separate sections, including anangular alignment section and a longitudinal transition sectioncomprising centering surfaces in accordance with various embodiments;

FIG. 61 shows an LCU that incorporates a compound groove having apositioning arrangement in accordance with various embodiments; and

FIG. 62 illustrates an optical ferrule having fiducials in accordancewith some embodiments.

The figures are not necessarily to scale. Like numbers used in thefigures refer to like components. However, it will be understood thatthe use of a number to refer to a component in a given figure is notintended to limit the component in another figure labeled with the samenumber.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Embodiments described herein involve optical cable subassemblies,optical connectors and related methods. Optical cables and connectorsused in many applications may make use of one waveguide or arrays ofmultiple parallel waveguides (typically 4, 8 or 12 or more parallelwaveguides). The individual waveguides are typically made of glass witha protective buffer coating, and the parallel waveguides are enclosed bya jacket. Optical cables and connectors including multiple waveguidecables and connectors are useful for connecting optical waveguides tooptical waveguides or to optoelectronic components for in-lineinterconnects and/or printed circuit board (PCB) connections, e.g.,backplane connections.

One type of connector is an expanded beam connector, in which light iscoupled between waveguides in a beam that is larger in diameter than thecore of an associated optical waveguide and typically somewhat less thanthe waveguide-to-waveguide pitch. The waveguides may comprise opticalfibers, e.g., a multi-mode fibers for a multi-mode communication system.These expanded beam optical connectors can have non-contact opticalcoupling and can require reduced mechanical precision when compared withconventional optical connectors.

FIG. 1 shows an optical cable subassembly 100 in accordance with someembodiments. The optical cable subassembly 100 includes one or moreoptical waveguides 110 and a light coupling unit 120 (also referred toherein as an optical ferrule). The term optical waveguide is used hereinto refer to an optical element that propagates signal light. An opticalwaveguide comprises at least one core with a cladding, wherein the coreand cladding are configured propagate light within the core, e.g., bytotal internal reflection. An optical waveguide may be, for example, asingle or multi-mode waveguide, a single core fiber, a multi-coreoptical fiber, or a polymeric waveguide. A waveguide may have anysuitable cross sectional shape, e.g., circular, square, rectangular etc.

In some embodiments, discussed in greater detail below, the opticalcable subassembly includes a cable retainer 130. The optical waveguidesare permanently attached to the light coupling unit 120 at a lightcoupling unit (LCU) attachment area 108. In embodiments that include acable retainer 130, the optical waveguides 110 are attached to theretainer 130 at the retainer attachment area 131.

The light coupling unit 120 is configured to mate, e.g.,hermaphroditically, with another light coupling unit. The light couplingunit 120 illustrated in FIG. 1 includes a mechanical mating tongue 116and light redirecting member 112. In some embodiments, the mechanicalmating tongue 116 can have a tapering width along at least a portion ofa length of the tongue portion as shown in the illustrations. Themechanical mating tongue 116 can extend outwardly from a front of aconnector housing (not shown in FIG. 1).

The light coupling unit (LCU) attachment area 108 includes plurality ofgrooves 114 each groove being configured to accommodate a differentoptical waveguide of the optical waveguides 110. The grooves areconfigured to receive an optical waveguide and each optical waveguide110 is permanently attached to a respective groove 114 at the lightcoupling unit attachment area 108, e.g., using an adhesive.

FIGS. 2A and 2B are cutaway views of a portion of an LCU focusing on thelight redirecting member. FIG. 2A illustrates the attachment of severaloptical waveguides 204 to light coupling unit 220. Optical fibers 204are aligned in grooves 214 to which they are permanently attached. Theexit end of optical fibers 204 is situated so as to be able to directlight emanating from the optical fiber into the input side or face oflight redirecting member 212. Light redirecting member 212 includes anarray of light redirecting elements 213, at least one for each opticalwaveguide 204 attached to light coupling unit 220. For example, invarious embodiments each light redirecting element 213 comprises one ormore of a prism, a lens, and a reflecting surface. Light redirectingmember 212 includes an array of light redirecting elements 213, one foreach optical waveguide of the optical waveguides (optical fibers) 204.

FIG. 2B is a cutaway view of a portion of an LCU that includes just onelight redirecting element 213, one waveguide alignment member, e.g.,groove 214, and one optical fiber 204. In this illustration, opticalfiber 204 is aligned in groove 214 and may be permanently attached toit. At the point of attachment, the fiber buffer coating and protectivejacket (if any) have been stripped away to allow only the bare opticalfiber to lie aligned and permanently affixed to groove 214. Lightredirecting element 213 includes light input side 222 for receivinginput light from first optical waveguide (optical fiber) 204 disposedand aligned at first waveguide alignment member 214. Light redirectingelement 213 also includes light redirecting side 224 that may include acurved surface for receiving light from the input side along an inputdirection and redirecting the received light along a differentredirected direction. The light redirecting element 213 also includesoutput side 226 that receives light from light redirecting side 224 oflight redirecting element 213 and transmits the received light as outputlight along an output direction toward a light redirecting member of amating light coupling unit.

FIG. 3 illustrates a side view of two optical cable subassemblies 301and 302 showing mated light coupling units 310 and 320 attached tooptical waveguides 311, 321 at light coupling unit attachment areas 313,323. A cable retainer 331, 332 is optionally attached to the opticalwaveguides 311, 321, at a retainer attachment area 341, 342. The lightcoupling units 310, 320 may be oriented at a predetermined mating angle,a, with respect to a mating direction. A bend 312, 322 in the opticalwaveguides 311, 321 between the light coupling unit attachment area 313,323 and the retainer attachment area 341, 342 (or other attachment area,e.g., in a connector housing) provides a predetermined amount of springforce to maintain the light coupling units 310, 320 in the matedposition.

Additional information regarding features and operation of lightcoupling units, optical cable subassemblies and optical connectors isdiscussed in commonly owned U.S. Patent Application 61/710,077 filed onOct. 5, 2012 which is incorporated herein by reference in its entirety.

FIGS. 4A through 4C provide several views of portions of an opticalconnector assembly 401. The optical connector assembly 401 comprises aninner housing 419 (shown in FIGS. 4B and 4C) that can hold one or moreoptical cable subassemblies 402. The inner housing 419 and a portion ofone or more optical cable subassemblies 402 are disposed within an outerhousing 418 (shown in FIG. 4A). FIGS. 4B and 4C illustrate one opticalcable subassembly 402 placed within the inner housing 419, however, theinner housing 419 in this example is capable of holding two opticalcable subassemblies. In general, the inner and outer housings can beconfigured to hold any convenient number of optical cable subassemblies.

The inner and outer housings, 419, 418, respectively, have a mating end451 and a non-mating end 452. One or more passageways 461, 462 aredisposed between the mating end 451 and the non-mating end 452 of theinner housing 419. Each passageway 461, 462 is dimensioned to receiveand contain a section of an optical cable subassembly. Optical cablesubassembly 402 is shown within passageway 461. The walls 461 a, 461 b,462 a, 462 b of the passageways 461, 462 between the retainer mount 411and the mating end 451 can be configured to support the optical cablesubassembly 402 while the optical cable subassembly 402 is in an unmatedposition. The walls 461 c, 461 d, 462 c, 462 d of the passageways 461,462 between the retainer mount 411 and the non-mating end 452 may beconfigured to support the optical cable subassembly 402 while theoptical cable subassembly 402 is in an unmated position or is in a matedposition.

In various embodiments, the passageways within the inner housing mayhave any shape and may have a smaller or a larger volume relative to thevolume occupied by the inner housing than the example passageways 461,462 shown in FIGS. 4A through 4C. The volume of a passageway issufficient to allow the optical waveguides of the optical cablesubassembly to develop the predetermined bend that provides the matingspring force. The bend 490 provides a spring force at the mating angleof the light coupling unit 471 that maintains the light coupling unit471 in optical communication with a mating light coupling unit 491 whenthe light coupling unit 471 is mated with a light coupling unit 491 of amating optical connector assembly 481 as illustrated by FIG. 4C.

The walls 461 a, 461 b, 461 c, 461 d, 462 a, 462 b, 462 c, 462 d of thepassageways 461, 462 may have any convenient shape, and are shown inFIG. 4C as curved walls in the forward section 455 a of the innerhousing (between the retainer mounts 411, 412 and the mating end 451).The curved walls 461 a, 461 b, 462 a, 462 b of passageways 461, 462accommodate a gentle -z direction bend 490 of the optical waveguides405. In some implementations, when the light coupling unit 471 is matedwith a mating light coupling unit, the light coupling unit 471 and theoptical waveguides 405 “float” within the inner housing 419 such thatneither the optical waveguides 405 nor the light coupling unit 471 touchthe curved walls 464 a, 464 b or other surfaces of the passageway 461 inforward section 455 a of the inner housing 419.

The inner housing 419 optionally includes one or more support features485 at the mating end 451 that support the optical waveguides 405 and/orthe light coupling unit 471 so that the light coupling unit 471 is in aposition for mating. In some embodiments, the position for mating may beangled with respect to the mating direction of the optical connectorassembly 401 as shown in FIG. 4A. The light coupling unit 471 is in amating position before it mates with another light coupling unit afterwhich (in some embodiments) the light coupling unit is in the “floating”mated position. In some embodiments, when in the mated position, thelight coupling unit 471 floats above support feature 485 b and belowsupport feature 485 a. In the example illustrated in FIGS. 4A-4C, thesupport features 485 comprise dual support arms that extend outwardlyfrom the passageways 461, 462.

The inner housing 419 includes retainer mounts 411, 412 in passageways461, 462. Retainer mount 411 is configured to couple with the cableretainer 421 of the optical cable subassembly 402. The section of theinner housing 419 that includes the retainer mounts 411, 412 and themating end 451, as indicated by arrow 455 a, is referred to herein asthe forward section of the inner housing 419. In the embodimentillustrated in FIGS. 4A through 4C, the mating end 451 includes lightcoupling unit support features 485 a, 485 b. The section of the innerhousing 419 that extends just behind retainer mounts 411, 412 andincludes the non-mating end 452, indicated by arrow 455 b, is referredto herein as the rear section 455 b of the inner housing 419. Couplingthe cable retainer 421 to the retainer mount 411 within the innerhousing 419 fixes the position of the retainer attachment area 403 ofthe optical cable subassembly 402 within the inner housing 419, or atleast fixes the position of the retainer attachment area 403 within theforward section 455 a of inner housing 419, when the optical cablesubassembly 402 is in the mated position.

In some embodiments, when the cable retainer 421 is installed in theretainer mount 411 and the optical cable subassembly 402 is in theunmated position, there may be some movement (e.g., along the x and or zaxes shown in FIG. 4B) of the cable retainer 421. When the optical cablesubassembly 402 mates with a compatible optical cable subassembly and isin the mated position, the position of the retainer attachment area 403of the optical cable subassembly 402 is fixed by the interaction of thecable retainer 421 and the retainer mount 411. Fixing the position ofthe retainer attachment area 403 provides for developing the springforce in the optical waveguides such that the light coupling unit 471 inthe mated position is able to float. The light coupling unit and theoptical waveguides are held away from the passageway walls 461 a, 461 band/or the supports 485 by the spring force of the optical waveguides405 and the optical waveguides 487 of a mating optical cable subassembly482 of a mating connector assembly 481 (as shown in FIG. 4C). In someembodiments, when the cable retainer 421 is coupled with the retainermount 411, the retainer attachment area 403 may be the only point ofattachment of the optical cable subassembly 402 to the inner housing 419that fixes the position of the optical cable subassembly 402. In themated position, the cable retainer 421 and the retainer mount 411support the optical cable subassembly 402 and attach the optical cablesubassembly 402 to the inner housing 419, fixing the position of theretainer attachment area 403 within the inner housing 419.

As illustrated in FIG. 4B, the retainer mount 411, 412 can be a slot inthe passageway 461, 462 dimensioned to hold the cable retainer 421, 422within the inner housing 419. The optical waveguides 405 of the opticalcable subassembly 402 bend, e.g., downwards in the passageway 461 in theorientation of FIGS. 4A-4C, in response to a force applied by a matingLCU. In some embodiments, the section of optical waveguides enclosedwithin the cable retainer 411 may be disposed at an angle with respectto the mating direction of the inner housing 419 when the optical cablesubassembly 402 is installed in the inner housing 419.

FIG. 5 depicts an embodiment of an inner housing 519 including fouroptical cable subassemblies 502 installed in the inner housing 519. Inthis embodiment, the cable retainers 521 are installed in complementaryretainer mounts 511 disposed near the non-mating end 552 of the innerhousing 519. Each of the optical cable subassemblies 502 include astrain relief boot 545 disposed outside the inner housing 519. In thisembodiment, the cable retainer 521 of each optical cable subassembly 502is arranged between the strain relief boot 545 and the light couplingunit 571. The cable retainer 521 includes an extension 561 a thatextends into the strain relief boot 545. In this example, the cableretainer 521 and complementary retainer mount 511 are arranged so thatthe section of the optical waveguides within the cable retainer 521 isdisposed about parallel with a mating direction of the opticalconnector.

The cable retainer and retainer mount can take on various complementaryshapes. FIGS. 4A-4C and 5 illustrate the retainer mount as a slot withthe cable retainer dimensioned to fit within the slot. FIGS. 6A, 6B and7A and 7B illustrate x-z plane cross sectional views of inner housings619, 719 with retainer mounts 611, 711 comprising groups of pegs 612,712 that extend laterally (along the y-axis) within a passageway 661,761. In these embodiments, optical cable subassemblies 605, 705 aredisposed within a passageway 661, 761 of the inner housing 619, 719 thatis shared by multiple optical cable subassemblies 605, 705. The cableretainers 621, 721 have holes 622 or slots 722 that fit the pegs 612,712 such that when the optical cable subassembly 605, 705 is installedwithin the inner housing 619, 719, the retainer attachment area 603, 703is at a fixed position within the passageway 661, 761 of the innerhousing, at least when the light coupling unit 671, 771 is in the matedposition.

FIG. 6A illustrates an inner housing 619 having retainer mounts 611,each retainer mount comprising a group of four pegs 612 disposed withinthe shared passageway 661. The cable retainers 621 of the optical cablesubassembly 605 comprise holes 622 that fit the pegs 612. FIG. 6Billustrates the inner housing 619 after the optical cable subassemblies605 have been installed. The light coupling unit support features 685comprise indentations in the sidewalls of the passageway 661 of theinner housing 619 which are dimensioned to receive the light couplingunits 671 and to support the light coupling units 671 at least when thelight coupling units 671 are in the position for mating. Other supportfeatures (not shown) in inner housing 619 may be provided to positionthe optical cable assembly.

FIG. 7A illustrates an inner housing 719 having retainer mounts 711,each retainer mount comprising a group of two pegs 712 disposed withinthe shared passageway 761. The cable retainers 721 (shown in FIG. 7B) ofthe optical cable subassemblies 705 comprise slots 722 that fit the pegs712. FIG. 7A illustrates the retainer mounts 711 prior to insertion ofthe optical cable subassemblies 705. FIG. 7B illustrates the opticalcable subassemblies 705 installed in the shared passageway 761 of theinner housing 719. As also illustrated in FIGS. 6A and 6B, the lightcoupling unit support features 785 shown in FIGS. 7A and 7B compriseindentations in the sidewalls of the passageway 761 of the inner housing719 that are dimensioned to receive the light coupling units 771.

FIGS. 6A, 6B, 7A, and 7B depict cable retainers comprising holes orslots and retainer mounts comprising pegs, however, it will beappreciated that the reverse could also be implemented wherein the cableretainers comprise pegs and the holes or slots are disposed in thehousing. An optical cable subassembly may be formed by attaching one ormore optical waveguides at the attachment area of a light coupling unit,the light coupling unit attachment area configured for receiving andpermanently attaching to the optical waveguides. The optical waveguidesare also attached to a cable retainer comprising a retainer attachmentarea for receiving and attaching to the optical waveguides. In someembodiments, attaching the optical waveguides to the cable retainercomprises inserting the waveguides, e.g., a linear array of waveguide,into a channel of the cable retainer by motion primarily along adirection parallel to the plane of the array of waveguides, andorthogonal to the direction of the waveguide axes. In some embodiments,attaching the optical waveguides to the cable retainer comprisesinserting the waveguides, e.g., a linear array of waveguides, into achannel of the cable retainer by motion primarily along a directionperpendicular to the plane of the array of waveguides, and orthogonal tothe direction of the waveguide axes.

A length of the optical waveguides between the light coupling unitattachment area and the retainer attachment area is configured to allowa bend to develop in the optical waveguides that provides apredetermined mating spring force at a predetermined angle and locationof the light coupling unit. In some embodiments, the optical cablesubassembly includes a boot that may be attached to the opticalwaveguides such that the cable retainer is disposed between the lightcoupling unit and the boot. In some embodiments, the boot may beconfigured to attach to the optical cable in a way that provides strainrelief for the optical cable.

FIG. 8A shows an example of a jig 800 made to facilitate fabrication ofan optical cable subassembly 801 including precise positioning of theretainer 821 on the optical waveguides 803. The light coupling unit871is first attached to the end of the optical waveguides 803, with thefibers aligned to the optical features of the light coupling unit withv-grooves, or other appropriate means. A cable retainer 821 is insertedinto a socket 811 in the jig 800, and the optical waveguides 803 withlight coupling unit 871 attached is then inserted into a groove 802 inthe jig 800 and the groove or other feature 822 in the cable retainer821. The optical waveguides 803 are gently pulled axially until thelight coupling unit 871 rests against a mechanical stop 872 in the jig800. Adhesive is then applied to the interior of the cable retainer 821,attaching the waveguides 803 to the cable retainer 821.

In some embodiments, the cable retainer may be attached to the opticalwaveguides first. Then the optical waveguides may be stripped andcleaved to a precise length before being attached to the light couplingunit. In yet other embodiments, the optical waveguides may be firststripped and cleaved before the cable retainer is attached at a precisedistance from the cleaved end. The light coupling unit may besubsequently attached.

The cable retainer may be attached to the optical waveguides by anysuitable means, including adhesive bonding to the jacket of the opticalwaveguides and/or to the optical waveguide buffers, adhesive bonding tobare fiber in a section where the jacket and buffer have been removed,mechanical clamping or crimping of the retainer onto the opticalwaveguides, welding or soldering to a metallized section of the fiber,or any combination of the above techniques. A strain relief boot may beattached to the cable retainer before the cable retainer is assembledinto the connector housing.

FIGS. 8B, 4B and 4A illustrate a process of making an optical connectorassembly in accordance with some embodiments. After the optical cablesubassembly 801 is fabricated, e.g., as discussed above, the length ofthe optical waveguides between the light coupling unit attachment area809 and the retainer attachment area 822 is L as shown in FIG. 8B. Theoptical cable subassembly 801 is installed into a connector innerhousing 819 as indicated by dashed line 899. In some embodiments, theoptical cable subassembly 801 is configured to be installed in andsubsequently removed from the housing 819 without damage to the innerhousing 819 or to the subassembly 801. The retainer 821 is coupled to acomplementary retainer mount 811 in the housing 819 such that the cableretainer 821 coupled with the complementary retainer mount 811 fixes aposition of the optical cable subassembly 801 within the housing 819 atleast when the optical cable subassembly 801 is in the mated position.The optical waveguides 803 are inserted into a passageway 861 of theinner housing 819 wherein the passageway 861 is shaped to constrain theoptical waveguides to bend within the housing 819 between the lightcoupling unit attachment area 809 and the retainer attachment area 822.As shown in FIGS. 4B and 4A, after the optical cable subassembly 402 isinserted into the housing 419, the straight-line distance, d, betweenthe light coupling unit attachment area 409 and the retainer attachmentarea 403 is less than L due to the bend that develops in the opticalwaveguides 405 when the optical cable subassembly 402 is installed inthe connector inner housing 419. After the optical cable subassembly 402is installed in the connector inner housing 419, an outer housing 420 isdisposed over the inner housing 419 as illustrated in FIG. 4A.

The cable retainer and the complementary retainer mount can take on avariety of shapes, a few of which are illustrated by FIGS. 9 through 25.FIGS. 9A through 9C illustrate a lateral cross sectional view, aperspective view, and a longitudinal cross sectional view, respectively,of cable retainer 900 in accordance with some embodiments. In theillustrated embodiment of FIGS. 9A through 9C, the cable retainer 900comprises a block 901 having an attachment surface 902 upon which theoptical waveguides 905 are bonded by an adhesive layer 906. As shown inFIGS. 9A through 9C, the adhesive layer 906 may be disposed between theblock surface 902 and the optical waveguides 905. In this example, andother examples where an adhesive is used to attach the opticalwaveguides to the cable retainer, the adhesive may be applied to thejacket, the buffer coating, and/or the cladding of the opticalwaveguides. In some configurations, the adhesive may be applied over theoptical waveguides and/or along the sides of the optical waveguides.FIGS. 9A through 9C provide an example of a unitary, single piece cableretainer.

FIGS. 10A and 10B are cross sectional views that illustrate anotherversion of a unitary, single piece cable retainer. In the illustratedembodiment, the cable retainer 1000 comprises a U-shaped piece 1001having sidewalls 1007 and an attachment surface 1002 between thesidewalls 1007. In the embodiment of FIG. 10A, the optical waveguides1005 are attached to the attachment surface 1002 by an adhesive layer1006 disposed between the attachment surface 1002 and the opticalwaveguides 1005. In the embodiment of FIG. 10B, the adhesive 1006 isdisposed under and over the optical waveguides 1005, e.g., substantiallyfilling the interior of the U-shaped piece 1001.

FIG. 11A is a perspective view of an embodiment of a unitary, singlepiece cable retainer 1100 and FIG. 11B shows an optical cablesubassembly 1190 that includes the cable retainer 1100. In theillustrated embodiment, the cable retainer 1100 comprises a C-shapedpiece 1101 having attachment surfaces 1103 a, 1103 b. In someembodiments, the optical waveguides 1105 may be adhesively attached toone or both of the attachment surfaces 1103 a, 1103 b. The C-shapedpiece 1101 can have an inner volume 1107 that is shaped to facilitateplacement of adhesive between the optical waveguides 1105 and one orboth of the inner attachment surfaces 1103 a, 1103 b.

FIG. 11B depicts an optical cable subassembly 1190 comprising a lightcoupling unit 1191 attached to the optical waveguides 1105 at lightcoupling unit attachment area 1192. The optical waveguides 1105 areattached to the cable retainer 1100 at a retainer attachment area 1103.As shown in FIG. 11B, the cable retainer 1100 may be attached to thebuffer coatings 1106 of the individual optical waveguides 1105 a-11051.The jacket 1194 that encloses the optical waveguides 1105 has beenstripped back but is still visible in FIG. 11B. In alternativeembodiments, the retainer 1100 may be attached to the jacket of theoptical waveguides rather than the buffer coatings. In some embodiments,both the jacket and the buffer coatings may be stripped back and theretainer is attached to the cladding of the individual opticalwaveguides 1105 a-11051.

In some embodiments, as illustrated by FIG. 11C, a single cable retainer1150 may be configured for attachment to two or more waveguides orwaveguide arrays 1161, 1162. If the retainer is attached to the jacketof the optical waveguides, the waveguides may move axially within thejacket and/or within their individual buffer coatings. If the jacket isstripped back and the retainer is attached to the buffer coatings, theaxial movement of the optical waveguides is decreased relative to theembodiment wherein the retainer is attached to the jacket. Attaching theretainer to the cladding of the optical waveguides provides the leastamount of axial movement of the waveguides and so is desirable in somecircumstances.

In some embodiments, the cable retainer may be a multi-piece structurewith separate pieces as illustrated by FIGS. 12-14. FIG. 12 illustratesa cross section in the x-y plane of a cable retainer 1200 comprising twoseparate pieces including a first piece 1201 having a surface 1202facing the optical waveguides 1205 and a second piece 1211 having asurface 1212 facing the optical waveguides 1205. The first and secondpieces 1201, 1211 are configured to attach together so that the opticalwaveguides 1205 are disposed between the first piece 1201 and the secondpiece 1211. In some embodiments, the first piece 1201 and the secondpiece 1211 may operate together as a clamp so that the opticalwaveguides 1205 are held in place by friction between the opticalwaveguides 1205 and surfaces 1202, 1212 of the first and second pieces1201, 1211. In some embodiments, the first piece 1201 and second piece1210 may be attached together by a mechanical fastener 1220, e.g., oneor more screws, rivets, clips, etc. In some embodiments, the first andsecond pieces 1202, 1212 may be adhesively attached together.Additionally or alternatively, the optical waveguides 1205 may beadhesively attached to one or both surfaces 1202, 1212 of the first andsecond pieces 1201, 1211. In some embodiments, the first and/or secondpieces may be attached together by latch parts (not shown in FIG. 12)disposed on the first and second pieces and configured to latch thefirst and second pieces together.

FIG. 13 provides another example of a cable retainer 1300 comprising twoseparate pieces including a first U-shaped piece 1301 and a secondplate-shaped piece 1311. As illustrated in the x-y cross sectionaldiagram of FIG. 13, the first and second pieces 1301, 1311 may beattached together by one or more of mechanical fasteners 1320, adhesive1306, latching parts (not shown in FIG. 13), etc. In some embodiments,the optical waveguides 1305 may be adhesively attached to the U shapedpiece 1301 in a manner similar to that described above in connectionwith FIGS. 10A or 10B before the first 1301 and second 1311 pieces areattached together.

The cable retainer may comprise two separate U-shaped pieces 1401, 1411as shown in the x-y cross sectional diagram of FIG. 14. In thisembodiment, the cable retainer 1400 comprises first 1401 and second 1411U-shaped pieces wherein the second U-shaped piece 1411 fits inside thefirst U-shaped piece 1401. The first and second pieces 1401, 1411 mayattach together and grip and hold the optical waveguides 1405 due to asnap fit or press fit that provides friction between the inner surfaces1403 of the sides of the first piece 1401 and the outer surfaces 1413 ofthe sides of the second piece 1411. Gripping of the fiber may beimproved by adding a compliant (e.g. elastomeric) pad or grommet 1407inside the U-shaped pieces which is pressed into contact with theoptical waveguides. The compliant structure may allow more securegripping without damage to the waveguides, or inducing micro-bendingloss. Additionally or alternatively, the first and second pieces 1401,1411 may be attached together by mechanical fasteners 1420, by adhesive1406, or by latching parts (not shown in FIG. 14). In someconfigurations, the optical waveguides 1405 may be adhesively attachedto the attachment surface 1402 of the first piece 1401 and/or theattachment surface 1412 of the second piece 1411.

In some implementations, as illustrated in the cross sectional diagramsof FIGS. 15A and 15B, the cable retainer 1500 may have a single piececonstruction with two portions that can move relative to one another.FIGS. 15A and 15B show, in x-y cross section, closed and open views,respectively, of a hinged cable retainer 1500 that includes a firstportion 1501 and a second portion 1511 connected by a hinge 1550 thatallows the first and second portions 1501, 1511 to move relative to oneanother. The hinge may comprise a “living hinge” comprising a thinflexible hinge made from the same material as the retainer pieces. Asabove, gripping of the fiber may be improved by adding a compliant (e.g.elastomeric) pad or grommet inside the U-shaped pieces which is pressedinto contact with the optical waveguides.

In some embodiments, in the closed position, the optical waveguides 1505are clamped and held between the first and second portions 1501, 1511 byfriction. In some embodiments, the cable retainer 1500 includescomplementary latch parts 1507 a, 1507 b, e.g., on a side of the cableretainer opposite the hinge 1550 as shown in FIGS. 15A and 15B, tofacilitate clamping the optical waveguides 1505 between the first andsecond portions 1501, 1511. Alternatively or additionally, the opticalwaveguides 1505 may be adhesively attached to the first and/or secondportions 1501, 1511.

In some embodiments, illustrated by FIGS. 16A, 16B, 17A, 17B, 17C and18, the retainer may comprise a collet with fingers configured to gripthe optical waveguides when the collet is pushed into a slot or sleeve.To ensure a strong mechanical bond to the glass waveguides, the shapesof the collet and the collet slot or sleeve may be tapered such thatwhen the collet is inserted into the inner housing, the collet iscompressed, causing it to clamp the optical waveguides. Gripping of thefiber may be improved by adding a compliant (e.g. elastomeric) pad orgrommet inside the U-shaped pieces which is pressed into contact withthe optical waveguides. In some embodiments, illustrated by FIGS. 16Aand 16B, the retainer 1621 includes a C-shaped collet piece 1601 withtwo or more collet fingers 1691, 1692 that can flex in the z directionunder force F. The optical waveguides 1605 are positioned within thecollet piece 1601 and the collet fingers 1691, 1692 extend laterally inthe y-direction across waveguides 1605. The retainer mount (shown inFIG. 16B), is a tapered slot 1611 formed in the passageway 1661 of aninner housing 1619 (only a portion of the inner housing 1619 is shown inFIG. 16B) such that when the cable retainer 1621 is inserted into theretainer mount 1611 the inner surfaces 1611 a, 1611 b of the slot 1611exert a force on the outer surfaces 1621 a, 1621 b of the fingers 1691,1692, causing the fingers 1691, 1692 to flex toward and grip the opticalwaveguides 1605 between the fingers 1691, 1692. In some embodiments, theoptical waveguides 1605 may be additionally affixed to the cableretainer 1621 by an adhesive, or other means.

FIGS. 17A through 17C provide another example of a collet-type cableretainer 1700. FIG. 17A provides an x-z side view of the of the retainer1700, FIG. 17B shows a y-z end view of the retainer 1700, and FIG. 17Cshows an x-z side view of the retainer 1700 disposed in a slot 1711 inan inner housing 1719.

The retainer 1700 includes a collet piece 1701 with two or more fingers1791, 1792 that can flex in the z direction under force F. The opticalwaveguides 1705 are positioned within the collet piece 1701 so that thefingers 1791, 1792 extend longitudinally in the x-direction alongwaveguides 1705. The retainer mount (shown in FIG. 17C), is a slot 1711formed in the passageway of an inner housing 1719 (only a portion of thepassageway and inner housing 1719 is shown in FIG. 17C) such that whenthe cable retainer 1700 is inserted into the retainer mount 1711, theinner surfaces 1711 a, 1711 b of the slot 1711 exert a force on theouter surfaces 1721 a, 1721 b of the fingers 1791, 1792 of the cableretainer 1700, causing the fingers 1791, 1792 to flex toward and gripthe optical waveguides 1705 between the fingers 1791, 1792. In someembodiments, the optical waveguides 1705 may additionally affixed to thecable retainer 1700 by an adhesive

In yet another example of a collet type retainer, the retainer 1800illustrated in FIGS. 18A and 18B includes a tapered collet piece 1801and a tapered sleeve piece 1811. The collet piece 1801 includes two ormore fingers 1802, 1803 configured to flex under force F. The opticalwaveguides 1805 are inserted through the collet piece 1801 and throughthe sleeve piece 1811 which are initially separated as shown in FIG.18A. When the collet piece 1801 is inserted into the tapered sleeve1811, as shown in FIG. 18B, the sleeve 1811 applies a force on thefingers 1802, 1803 causing the fingers 1802, 1803 to flex toward andgrip the optical waveguides 1805 between the fingers 1802, 1803. In someembodiments, the optical waveguides 1805 may alternatively oradditionally affixed to the collet piece 1801 by an adhesive. In variousembodiments, the inside of the sleeve may be tapered, or both the insideof the sleeve and outside of the collet may be tapered.

In some embodiments, e.g., wherein the retainer is configured to attachto the optical waveguides by a friction grip, the optical waveguides mayslide longitudinally along the x-axis through the retainer until theappropriate length of the optical waveguides is reached. When theappropriate length is reached, the optical waveguides are fixedlyattached to the retainer by a clamping action of the retainer. Initiallyallowing the optical waveguides to slide until the retainer clamps andgrips the waveguides, thus fixing the position of the retainer on thewaveguides, may facilitate fabrication of the optical cable subassemblyand/or optical connector assembly in some circumstances.

In some embodiments, the cable retainer may include surface featuresthat facilitate alignment of the individual optical waveguides. Oneexample of a cable retainer with surface features is shown in FIG. 19.FIG. 19 depicts a cross sectional y-z view of a retainer 1900 comprisinga block 1901 having an attachment surface 1902 for attaching to aoptical waveguides which are not shown in FIG. 19. The attachmentsurface 1902 includes grooves 1907, e.g., U, V, and/or Y shaped grooves,wherein each groove 1907 is dimensioned to accommodate one opticalwaveguide. The grooves 1907 facilitate alignment of the individualoptical waveguides in the retainer 1900. The optical waveguides 1905 maybe gripped by the retainer and/or adhesively attached to the retainer1900.

In some embodiments, one or both exit surfaces of one or both ends ofthe cable retainer may have a particular shape, e.g., rounded, squared,beveled, etc. Rounded or beveled exit surfaces may be used toaccommodate a bend in the optical waveguides. FIG. 20 illustrates across section in the x-z plane of an optical cable subassembly 2000comprising a light coupling unit 2010, one or more optical waveguides2020, and a cable retainer 2030. The cable retainer 2030 comprises aretainer piece 2001 having first end 2001 a and a second end 200 lb. Atthe first end 2001 a, the retainer piece 2001 has first exit surface2011 with a rounded edge and a second exit surface 1612 with a roundededge. The first and exit surfaces 2021, 2022 at the second end 160 lb ofthe retainer piece 1601 have square edges. In some embodiments, thecable retainer piece (or multiple pieces) may include grooves or recessfeatures that provide a bonding space for adhesive, as illustrated byfeatures 2005 of FIG. 20. Bonding spaces 2005 as shown in FIG. 20, forexample, may be used in any of the cable retainers described herein thatrely on adhesive bonding to secure the optical waveguides to theretainer. These bonding spaces can improve the strength of the adhesivebond to the cable retainer by increasing the surface area of the bondedregion, and/or by creating a mechanical interlock between the adhesiveand the cable retainer. The bonding spaces can also be used to controlthe flow of excess adhesive and prevent it from contaminating theoutside surface of the cable retainer, thus interfering with itsintended fit into the retainer mount.

FIG. 21 depicts an optical cable subassembly 2100 comprising a lightcoupling unit 2110, a plurality of optical fibers 2105 and a keyed cableretainer 2130. The cable retainer 2130 includes a peg, e.g., acylindrical peg, having a first side or portion 2101, a second side orportion 2111, wherein the first side 2101 includes a key 2102. Theoptical waveguides 2105 are attached between the first side 2101 and thesecond side 2111. The optical waveguides 2105 may be held in the cableretainer 2130 between the first and second sides 2101, 2111 by adhesive2106 and/or friction grip. When an adhesive is used, the cable retainer2130 includes an adhesive slot 2117 between the retainer sides orportions 2101, 2111 where the optical waveguides 2105 are adhesivelyattached to the cable retainer 1230. The cable retainer 2130 isconfigured to fit into a complementary keyed slot of the inner housing(not shown in FIG. 21).

In some embodiments, the cable retainer can serve as both a strainrelief and an optical waveguide retainer. In these embodiments, thecable retainer includes first and second regions, a first region of thecable retainer, which is the strain relief section, is attached to thejacket of the plurality of the optical waveguides. A second region ofthe cable retainer is attached to the cladding and/or buffer coating ofthe optical waveguides. To facilitate attaching to both the jacket andthe cladding and/or buffer coatings, some embodiments, illustrated byFIGS. 22 and 23, include an adhesive attachment space wherein the width(along the z axis) of the adhesive attachment space between the piecesor portions of the cable retainer that adhesively attach to the opticalwaveguides may vary. An example of a variable width attachment space2217 is shown in FIG. 22. FIG. 22 depicts a portion of an optical cablesubassembly 2200 including optical waveguides 2205 and a cable retainer2230. The optical waveguides 2205 are disposed within the variable widthadhesive attachment space 2217 of the cable retainer 2230. The adhesiveattachment space includes a first region 2217 a, having a width s₁, anda second region 2217 b, having a width s₂, wherein s_(i) is less thans₂.

The first region 2217 a of the adhesive attachment space 2217 isconfigured to adhesively attach to first regions 2205 a of the opticalwaveguides 2205 that have the jacket 2208 stripped away from the opticalwaveguides 2205. In the first regions 2205 a of the optical waveguides2205, the buffer coating 2207 of the optical waveguides 2205 is exposedand adhesive 2206 is disposed between the buffer coating 2207 and theinner surfaces 2217 a, 2217 b of the adhesive attachment space 2217 ofthe cable retainer 2230. The height si of the adhesive attachment space2217 at the opening 2217 c of the adhesive attachment space 2217 isrelatively narrow which controls the angle of the optical waveguides2205 at the opening 2217 c.

The second region 2217 b (strain relief region) of the adhesiveattachment space 2217 is configured to adhesively attach to secondregions 2205 b of the optical waveguides 2205. In the second regions2205 b of the optical waveguides 2205, the jacket 2208 of the opticalwaveguides 2205 has not been stripped away from the optical waveguides2205. In the second region 2205 b of the optical waveguides 2205,adhesive 2206 is disposed between the jacket 2208 of the opticalwaveguides 2205 and the inner surfaces 2218 a, 2218 b of the adhesiveattachment space 2217 of the cable retainer 2230.

In other embodiments (not shown) the width of the adhesive attachmentspace 2217 does not substantially vary.

Another example of a cable retainer having a strain relief sectionfacilitated by a variable height attachment space 2317 is shown in FIG.23. FIG. 23 depicts a portion of an optical cable subassembly 2300including optical waveguides 2305 and a cable retainer 2330. The opticalwaveguides 2305 are disposed within the variable width adhesiveattachment space 2317 of the cable retainer 2330. The adhesiveattachment space includes a first region 2317 a, having a height s₃, anda second region 2317 b (the strain relief section) having a height s₄,where s₄ is greater than s₃.

The first region 2317 a of the adhesive attachment space 2317 isadhesively attached to regions of the optical waveguides that have thejacket removed and/or to regions of the optical waveguides that haveboth the jacket 2308 and the buffer coating 2307 stripped away exposingthe cladding 2309 of the optical waveguides 2305. In the first region2317 a, adhesive 2306 is disposed between the buffer coating 2307 and/orcladding 2309 of the optical waveguides 2305 and the inner surfaces 2317a, 2317 b of the adhesive attachment space 2317 of the cable retainer2330.

In some implementations, bonding the cable retainer 2330 to the cladding2309 of the optical waveguides may provide a more reliable bond and/ormay reduce the amount of longitudinal movement of the individual opticalwaveguides within their buffer coating 2307 and/or the jacket 2308 ofthe optical waveguides.

The second (strain relief) region 2317 b of the adhesive attachmentspace 2317 is configured to adhesively attach to a region of the opticalwaveguides 2305 where the jacket is intact. In the second region 2317 b,adhesive 2306 is disposed between the jacket 2308 of the opticalwaveguides 2305 and the inner surfaces 2317 a, 2317 b of the adhesiveattachment space 2317 of the cable retainer 2330.

In other embodiments (not shown) the width adhesive attachment space2317 does not substantially vary.

In some embodiments, the optical cable subassembly includes a boot thatcovers a portion of the optical waveguides. The boot is often positionedoutside the connector housing at or near the non-mating end of theconnector housing. The cable retainer is positioned between the boot andthe light coupling unit. The boot may be made of a flexible materialwhich protects the optical waveguides from breakage or damage due tooverflexing.

FIG. 24A is a cross sectional diagram of an optical cable subassembly2400 that includes a light coupling unit 2410, one or more opticalwaveguides 2420, a cable retainer 2430, and a boot 2440. In theillustrated embodiment, the boot 2440 and the cable retainer 2430 arespaced apart along the optical waveguides 2420. Each optical waveguide2420 has a cladding 2409 surrounding an optical core with a buffercoating 2407 disposed over the cladding 2409. A jacket 2408 is disposedover the optical waveguides 2420. In some sections 2420 a, 2420 b of theoptical waveguides 2420, the jacket 2408, the buffer coating 2407, orboth are stripped away to facilitate attachment of the opticalwaveguides 2420 at the light coupling unit attachment area 2411 and/orthe retainer attachment area 2431.

In some embodiments, the optical cable subassembly may include a cableretainer that is shaped or angled such that the optical waveguides arebent or angled within the retainer. FIG. 24B depicts an optical cablesubassembly 2490 comprising a light coupling unit 2491, a boot 2494 anda cable retainer 2493 disposed between the light coupling unit 2491 andthe boot 2494. The cable retainer 2493 is shaped so that the opticalwaveguides 2492 include a bend 2495 within the cable retainer 2493.

FIG. 24C depicts an optical cable subassembly comprising a lightcoupling unit 2481, a boot 2484 and a cable retainer 2483 disposedbetween the light coupling unit 2481 and the boot 2484. The cableretainer 2483 is shaped so that the portion 2485 of the opticalwaveguides 2482 within the cable retainer 2483 is angled.

In some embodiments, as shown in FIG. 25, the boot and the cableretainer may be overlapping and/or may be attached together. FIG. 25illustrates an embodiment wherein the cable retainer 2530 includes anextension 2531 that extends through the passageway 2561 of the innerhousing, outside the inner connector housing 2519, and inside the boot2540.

In various embodiments, the optical connector assembly may include aprotective cover to protect the light coupling units from damage orcontamination. FIGS. 26 through 29 illustrate several protective coverconfigurations. FIG. 26 shows mating optical connector assemblies 2601,2602 having male 2610 and female 2620 protective covers on the outerhousings that extend over the light coupling units 2671. In theillustrated embodiment, the protective covers are fixed on theconnectors, and do not move during mating, e.g., the female cover doesnot move relative to the female connector.

FIG. 27 provides a side view of mating hermaphroditic connectorassemblies 2701, 2702 having inner 2719, 2729 and outer housings 2718,2728. The light coupling units 2771, 2772 are shown disposed within theinner housings 2719, 2729. Each connector assembly 2701, 2702 includes aseparate, removable protective cover 2703, 2704 that is disposed overthe mating end of the outer housing 2718, 2728. The protective covers2603, 2704 are configured to be manually removed before the connectorassemblies 2701, 2702 are mated.

FIG. 28 provides a side view of mating hermaphroditic connectorassemblies 2801, 2802 having inner 2819, 2829 and outer housings 2818,2828. The light coupling units 2871, 2872 are shown disposed within theinner housings 2819, 2829. Each connector assembly 2801, 2802 includes aprotective cover 2803, 2804 coupled to the outer housing 2718, 2728 by ahinge 2705, 2706. The protective covers 2803, 2805 are moved via thehinges 2805, 2806 to expose the light coupling units 2871, 2872 beforethe connector assemblies 2801, 2802 are mated.

FIGS. 29A and 29B depict side views of hermaphroditic connectorassemblies 2901, 2902 having spring actuated retractable protectivecovers. FIG. 29A shows the position of the protective cover 2903 ofconnector assembly 2901 prior to mating. FIG. 29B shows the position ofprotective covers 2903, 2904 after mating. The hermaphroditic connectorassemblies 2901, 2902 have inner 2919, 2929 and outer housings 2918,2928. The light coupling units 2971, 2972 are shown disposed within theinner housings 2919, 2929. Each connector assembly 2901, 2902 includes aretractable protective cover 2903, 2904 actuated by a spring 2905, 2906.The protective covers 2903, 2905 are pushed back, compressing thesprings 2905, 2906 as the connector assemblies 2901, 2902 are mated.

Expanded-beam optical interconnect devices, such as single mode lightcoupling units, are sensitive to angular errors on the order of 0.1degrees. For example, the planar interface between light coupling unitsof the present disclosure can be about 3 mm long. If a single 50 μmdiameter dust particle is trapped in the interface between two matedlight coupling units, the dust particle would generate an angular errorof 1 degree or larger, thereby decreasing optical transmissionefficiency. Embodiments are directed to a light transmitting surface,such as a mating surface of a light coupling unit, that incorporates aseries of grooves, posts or other features or patterns configured tocapture particulate contaminates, such as dust, when the mating surfacecontacts a corresponding mating surface of a mating light coupling unit.In order to make mating between light transmitting surfaces lesssensitive to dust, a series of small lands with grooves between them (orposts with spacing therebetween) can be added to the planar sections ofthe light transmitting surface so that there is a place for the dust orother particulate contaminate to fall into. Although the followingdiscussion is directed to a light coupling unit or units, it isunderstood that any light transmitting surface or surfaces arecontemplated.

Turning now to FIGS. 30-34, there are illustrated different views of anLCU 3000 which incorporates a feature for capturing particulatecontaminants in accordance with various embodiments. The LCU 3000illustrated in FIGS. 30 and 32 includes a first major surface 3001 onwhich an LCU attachment area 3002 is provided. The LCU 3000 furtherincludes sidewalls 3022 and rear wall 3024. The LCU attachment area 3002is shown positioned between the sidewalls 3022 and includes a pluralityof substantially parallel first grooves 3010 oriented along a firstdirection. A light redirecting member 3004 is provided at the end ofeach of the first grooves 3010. The first grooves 3010 are configured toreceive a optical waveguides (not shown). The first major surface 3001also includes a mating tongue 3012 that projects outwardly from the LCUattachment area 3002. The mating tongue 3012 includes a first surface3013 and an opposing second surface 3015. Adjacent the LCU attachmentarea 3002 is the rear wall 3024 which includes a coupling member 3014.The coupling member 3014 is configured to receive a mating tongue 3012of a mating light coupling unit.

FIGS. 31 and 33 illustrate various features of the LCU 3000 provided ona second major surface 3021, the second major surface 3021 opposing thefirst major surface 3001 shown in FIGS. 30 and 32. The second majorsurface 3021 is configured to be a mating surface of the LCU 3000. Thesecond major surface 3021 includes the second surface 3015 of the matingtongue 3012 which, in the embodiment shown in FIGS. 31 and 33, issubstantially planar. The second major surface 3021 also includes aplurality of substantially parallel second grooves 3020 and an opticallytransmitting window 3016 disposed between the second grooves 3020 andthe second surface 3015 of the mating tongue 3012. The second grooves3020 are oriented along a direction different from the first directionof the first grooves 3010 provided at the LCU attachment area 3002 onthe first major surface 3001. The second grooves 3020 are oriented alonga direction different from the mating direction, D_(M). The secondgrooves 3020 have a pitch different from that of the first grooves 3010.

In the embodiment shown in FIGS. 31 and 33, the second surface 3015 ofthe mating tongue 3012 is substantially planar. In other embodiments,the second surface 3015 of the mating tongue 3012 includes a pluralityof the substantially parallel second grooves 3020. The second grooves3020 on the second surface 3015 of the mating tongue 3012 are orientedalong a direction different from the mating direction, D_(M).

As discussed above, the second major surface 3021 is configured to be amating surface of the LCU 3000. In particular, the second major surface3021 is adapted to slide against the mating surface of a mating lightcoupling unit when moved in a mating direction, D_(M) (see FIG. 31). Theinterior surfaces of the sidewalls 3022 have a shape configured toreceive the shape of a mating tongue 3012 of a mating light couplingunit. In the embodiment shown in FIGS. 31 and 33, the interior surfacesof the sidewalls 3022 have a curvature that matches the curvature of themating tongue 3012 of the mating light coupling unit. It is understoodthat the interior surfaces of the sidewalls 3022 can instead bepolygonal or include polygonal features in addition to curved features.

In the embodiment shown in FIGS. 31 and 33, the optically transmittingwindow 3016 is recessed into the second major surface 3021. Moreparticularly, the optically transmitting window 3016 is recessed belowthe second surface 3015 of the mating tongue 3012 and below the lands3023 of the second grooves 3020. Recessing the optically transmittingwindow 3016 into the second major surface 3021 prevents potentiallydamaging contact with a mating tongue 3012 of a mating light couplingunit when the LCU 3000 is connected to a mating light coupling unit.

According to various embodiments, the second grooves 3020 on the secondmajor surface 3021 are configured to capture particulate contaminants(e.g., dust) between the second major surface 3021 and a mating surfaceof a mating light coupling unit. For example, as the mating tongue 3012of the mating light coupling unit is received by the coupling member3014, any particulate contaminants on the mating tongue 3012 of themating light coupling unit or on a land 3023 of the second grooves 3020are pushed into and captured by a recess of the second grooves 3020.Capturing of particulate contaminants within the recesses of the secondgrooves 3020 prevents the above-described angular errors from occurringwhen mating a pair of light coupling units.

In the embodiment shown in FIGS. 31 and 33, the second grooves 3020 onthe second major surface 3021 are oriented transverse to the firstdirection of the first grooves 3010 on the first major surface 3001. Insome embodiments, the second grooves 3020 are oriented substantiallyperpendicular to the first direction of the first grooves 3010. In otherembodiments, the second grooves 3020 can be oriented at an angle ofabout 45° with respect to the first direction of the first grooves 3010.In further embodiments, the second grooves 3020 can be oriented at anangle between about 30° and 60° with respect to the first direction ofthe first grooves 3010. Although the second grooves 3020 are shown inFIGS. 31 and 33 to be substantially parallel and straight, the secondgrooves 3020 can have some degree of curvature while maintaining asubstantially parallel relationship. For example, the second grooves3020 can have a generally chevron shape or other curved shape.

The second grooves 3020 can have cross-sections that comprise polygonalsurfaces and/or curvilinear surfaces. In some embodiments, the secondgrooves 3020 have a V-shaped cross section. In other embodiments, thesecond grooves 3020 have a U-shaped cross section. The second grooves3020 comprise a series of lands 3023 and a recess between adjacent lands3023. In some embodiments, the lands 3023 have a width smaller than awidth of the recesses. For example, the width of the lands 3023 can beless than about half the width of the recesses. By way of furtherexample, the width of the lands 3023 can be less than about one-fourththe width of the recesses. In other embodiments, the lands 3023 have awidth larger than a width of the recesses. In further embodiments, thewidth of the lands 3023 is less than about 75 μm. The lands 3023 may becoplanar with any mating surface, such as a mating surface that does nothave lands. It is noted that if the lands 3023 are narrower than therecesses, and there is a linear pattern where the lands 3023 areparallel on the two mating parts, the lands 3023 can fall into therecesses and jam. Accordingly, if the lands 3023 are linear and notsufficiently parallel, they will not cause jamming.

FIGS. 34-37 illustrate an LCU 3000 having a groove configuration on thesecond major surface 3021 in accordance with various embodiments. TheLCU 3000 shown in FIGS. 34 and 36 includes a first major surface 3001having many of the features shown in FIGS. 30 and 32. The LCU 3000 shownin FIGS. 34 and 36 includes a second major surface 3021 having featuresdiffering from those shown in FIGS. 31 and 33. More particularly, andwith reference to FIGS. 35 and 37, the second surface 3015 of the matingtongue 3012 includes a plurality of substantially parallel secondgrooves 3020. In this embodiment, the second major surface 3021 includesa first region 3030 comprising at least some of the second grooves 3020and a second region 3032 comprising at least some of the second grooves3020, wherein the second region 3032 includes the second surface 3015 ofthe mating tongue 3012.

The second grooves 3020 on the second major surface 3021 are orientedalong a direction different from the first direction of the firstgrooves 3010 of the LCU attachment area 3002. In the embodiment shown inFIGS. 35 and 37, the second grooves 3020 are oriented at an angle ofabout 45° with respect to the first direction of the first grooves 3010.In general, the second grooves 3020 can be oriented at an angle betweenabout 30° and 60° with respect to the first direction of the firstgrooves 3010.

A diagonal orientation of the second grooves 3020 serves to reducechattering that can occur during light coupling unit mating where thesecond grooves 3020 are oriented perpendicular to the direction ofmating, D_(M). Although the second grooves 3020 are shown in FIGS. 35and 37 to be substantially parallel and straight, the second grooves3020 can have some degree of curvature while maintaining a substantiallyparallel relationship.

In the embodiment illustrated in FIGS. 35 and 37, an opticallytransmitting window 3016 is situated between the first region 3030 andthe second region 3032. The upper surface of the optically transmittingwindow 3016 is flush with the lands 3023 of the second grooves 3020 inthe first and second regions 3030 and 3032. Positioning the opticallytransmitting window 3016 to be flush with the lands 3023 of the secondgrooves 3020 facilitates clearing of any particulate contaminants fromthe optically transmitting window 3016 when connecting the LCU 3000 to amating light coupling unit. When connecting a pair of light couplingunits, for example, the second grooves 3020 on region 3032 of the matingtongue 3012 of a mating light coupling unit slidably contacts theoptically transmitting window 3016 of the LCU 3000, thereby pushing anyparticulate contaminates off of the optically transmitting window 3016.

Because the optically transmitting window 3016 comes into contact withthe mating tongue 3012 of a mating light coupling unit, it is desirablethat the optically transmitting window 3016 have enhanced hardness. Moreparticularly, the optically transmitting window 3016 can have a hardnessgreater than that of the lands 3023 of the second grooves 3020. Forexample, the optically transmitting window 3016 can include a coatinghaving a hardness greater than that of the lands 3023 of the secondgrooves 3020. The coating on the optically transmitting window 3016 canbe an antireflective coating, for example.

FIG. 38 illustrates an LCU 3000 having a pattern of small posts 3025 onthe second major surface 3021 in accordance with various embodiments.The LCU 3000 shown in FIG. 38 includes a first major surface (not shown)having many of the features shown in previous figures (e.g., one or moregrooves configured to receive one or more optical waveguides). The LCU3000 shown in FIG. 38 includes a second major surface 3021 having afield of small posts 3025 that extend normal from the second majorsurface 3021. Top surfaces of the posts 3025 define lands. The spacingbetween the posts 3025 allows dust and other particulate contaminants tobe captured within recesses between the posts 3025. In some embodiments,the posts 3025 are arranged in rows and columns. In other embodiments,the posts 3025 are arranged in a staggered pattern or otherdistribution. The second surface 3015 of the mating tongue 3012 ispreferably planar, which becomes a mating surface for posts of a matingLCU.

FIG. 39 illustrates an LCU 3000 having a waffle pattern 3027 on thesecond major surface 3021 in accordance with various embodiments. TheLCU 3000 shown in FIG. 39 includes a first major surface (not shown)having many of the features shown in previous figures. The LCU 3000shown in FIG. 39 includes a second major surface 3021 having a wafflepattern 3027 extending over the second major surface 3021 except for theoptically transmitting window 3016. In some embodiments, the wafflepattern 3027 can cover the region of the second major surface 3021 thatexcludes the mating tongue 3012 and the optically transmitting window3016. The lands (raised portions) of the waffle pattern 301 are arrangedto contact corresponding lands or planar surfaces of a waffle pattern orplanar surface provided on a mating LCU. The waffle pattern 3017 of FIG.39 has a rectangular pattern. In other embodiments, patterns such ashexagonal patterns, diamond patterns, or irregular patterns may be used.

FIGS. 40A-40C illustrate coupling between two LCUs 3000A and 3000B alonga mating interface 3030. The mating interface 3030 includes a firstmating interface 3030A between a mating tongue surface 3012A of LCU3000A and a mating surface 3003B of LCU 3000B. The mating interface 3030also includes a second mating interface 3030B between a mating tonguesurface 3012B of LCU 3000B and a mating surface 3003A of LCU 3000A. InFIG. 40A, the mating interface 3030 of the two LCUs 3000A and 3000B doesnot include a particulate contaminant capture feature of the presentdisclosure. In the absence of particulate contaminants at the matinginterface 3030, the optical transparent portions 3016A and 3016B are inproper optical alignment.

FIG. 40B shows a dust particle 3032 trapped at the second matinginterface 3030B between the mating surface 3003A of LCU 3000A and thetongue mating surface 3012B of LCU 3000B. As was discussed previously,presence of a single 50 um diameter dust particle trapped in theinterface 3030 between the two mated LCUs 3000A and 3000B can generatean angular error of 1 degree or larger at the optical interface3016A/3016B.

FIG. 40C shows coupling between two light coupling units 3000A and 3000Beach incorporating a particulate contaminant capture feature inaccordance with various embodiments. FIG. 40C illustrates a dustparticle 3032A captured within one of the second grooves 3020A at asecond mating interface 3030B between LCU 3000A and LCU 3000B. Moreparticularly, the dust particle 3032A is captured within a recess of oneof the grooves 3020A at the second mating interface 3030B between themating surface 3003A of LCU 3000A and the mating tongue surface 3012B ofLCU 3000B.

FIG. 40C also illustrates a dust particle 3032B captured within one ofthe second grooves 3020B at a first mating interface 3030A between LCU3000A and LCU 3000B. More particularly, the dust particle 3032B iscaptured within a recess of one of the grooves 3020B at the first matinginterface 3030A between the mating surface 3003B of LCU 3000B and themating tongue surface 3012A of LCU 3000A. Because the dust particles3032A and 3032B are trapped within the particulate contaminant capturefeatures, proper optical alignment at the optical interface 3016A/3016Bbetween LCU 3000A and LCU 3000B is maintained.

Attachment of optical waveguides or fibers to optical or optoelectronicdevices is often done with V-shaped grooves (i.e., V-grooves). Thewaveguides is forced into the bottom of the groove (typically a 90°angle V-groove) with a clamping mechanism. Typically, an index-matchingadhesive is then applied to permanently hold the waveguides in theV-groove. This scheme has several challenges. The clamping mechanismmust provide sufficient force to bend the waveguides to seat them in andthus align them with the grooves, yet have sufficient compliance tocontact each waveguide of a ribbon of waveguides. It must also allowaccess for the application of the adhesive without itself becomingbonded to the waveguides. The position of the clamping mechanism overthe V-grooves makes it difficult to observe the positions of thewaveguides, or to use a light-cured adhesive. Use of U-shaped grooves(i.e., U-grooves) with flat bottoms and vertical sidewalls have severalchallenges. Issues with the ease of capture of the waveguides and withthe positional error associated with the clearance required for thegroove width have not been previously addressed.

Embodiments are directed to a light coupling unit having one or amultiplicity of grooves configured to receive and permanently attach toone or a multiplicity of optical waveguides. In one embodiment, aportion of a groove provides nearly vertical sidewalls that allow anoptical waveguide to be bent laterally into the correct position. Thegroove can be formed wider at the top, providing a substantiallyY-shaped cross-section (i.e., Y-groove) that facilitates capturing anoptical waveguide into the groove. As was discussed previously, theoptical waveguides can be single-mode optical waveguides, multi-modeoptical waveguides, or an array of single-mode or multi-mode opticalwaveguides. In some embodiments, the waveguides are single-mode or amulti-mode polymer optical waveguide.

In another embodiment, a portion of a groove provides nearly verticalsidewalls that allow an optical waveguide to be bent laterally into thecorrect position. This portion of the groove can be made slightly widerthan the diameter of the optical waveguide to provide clearance forinitial capture of the optical waveguide. Once in contact with andapproximately parallel to the bottom of the groove, the end of theoptical waveguide is slid axially into a location where the width of thegroove gradually narrows to less than the diameter of the opticalwaveguide. Here the tip of the optical waveguide stops, and is correctlypositioned. The groove, according to some embodiments, can be formedwider at the top, providing a substantially Y-shaped cross-section thatfacilitates capturing an optical waveguide into the groove.

Embodiments of the disclosure can provide several advantages overconventional approaches. For example, like V-grooves, Y-grooves can bemolded in the same mold insert as the light redirecting members (e.g.,mirror lenses) of a light coupling unit. The waveguides can be easilyand very quickly positioned in the Y-grooves. The waveguides can beprecisely positioned without the use of a clamp over the grooves (seeFIGS. 49-55), which allows for direct observation of the waveguides inthe grooves and the use of light-cured adhesive to rapidly and reliablyattach the waveguides in the Y-grooves.

FIG. 41 illustrates a portion of an LCU 4100 in accordance with variousembodiments. The LCU 4100 shown in FIG. 41 includes a single LCUattachment area 4102. Although a single LCU attachment area 4102 isshown in FIG. 41, it is understood that a multiplicity of attachmentareas 4102 can be provided on the LCU 4100 for receiving and permanentlyattaching to a multiplicity of optical waveguides. The LCU attachmentarea 4102 includes a Y-groove 4110 having an entrance 4111, a terminalend 4113, and a central plane 4112 (see FIG. 42) extending between theentrance 4111 and the terminal end 4113. The central plane 4112, asshown in FIG. 42, is a plane bisecting a bottom surface 4125 of theY-groove 4110 and extending perpendicularly from the bottom surface4125. The Y-groove 4110 is configured to receive an optical waveguide,such as the generally cylindrical waveguide 4105 shown in FIG. 42.

The LCU 4100 includes a light redirecting member 4104 and anintermediate section 4108 between the light redirecting member 4104 andthe terminal end 4113. In some embodiments, the terminal end 4113comprises an optically clear member, such as a lens, or is formed fromoptically transparent material. The intermediate section 4108 is formedfrom an optically transparent material. The light redirecting member4104 includes an output side 4106 through which light exits from (orenters into) the light directing member 4104.

According to some embodiments, and with reference to FIGS. 41 and 42,the Y-groove 4110 is a compound groove formed by a generally U-shapedlower portion 4120 and an expanded upper portion making the compoundgroove generally Y-shaped. It is understood that the terms U and Ymodifying the term groove serve to connote an approximate shape of thesegrooves for purposes of convenience and not of limitation.

As is best seen in FIG. 42, the Y-groove 4110 is defined by a firstregion 4120′, a second region 4130′, an opening 4140, and a bottomsurface 4125. The first region 4120′ is defined between the bottomsurface 4125 and the second region 4130′. The first region 4120′includes substantially parallel sidewalls 4122 separated by a spacing,S. The sidewalls 4122 can have a draft of one or a few degrees (e.g.,<about 10 degrees) in a direction off vertical, and as such, may beconsidered to be substantially parallel to one another. For example, thesidewalls 4122 can be normal to the bottom surface 4125 to within about5 degrees. The sidewalls 4122 can have a slight outward slope or draftto facilitate mold release of the sidewalls 4122 during fabrication. Inthis case, the substantially vertical sidewalls 4122 form a draft angle,α, with a plane 4112 extending perpendicular from the bottom surface4125.

The second region 4130′ is disposed between the first region 4120′ andthe opening 4140. The opening 4140 is defined between top surfaces 4127of the Y-groove 4110. A width, W, of the opening 4140 is greater thanthe spacing, S, between the sidewalls 4122. As can be seen in FIG. 42,the first region 4120′ defines the U-shaped lower portion 4120 ofY-Y-groove 4110 and the second region 4130′ defines the expanded upperportion 4130.

The second region 4130′ includes sidewalls 4132 that extend outwardlyfrom the central plane 4112 of the Y-groove 4110. In FIG. 42, thesidewalls 4132 comprise linear sidewalls, which may be consideredchamfered sidewalls. In other embodiments, the sidewalls 4132 may benon-linear, such as by having some degree of curvature. The sidewalls4132 extend between the first region 4120′ and the opening 4140, with aspacing between the sidewalls 4132 progressively increasing from thefirst region 4120′ to the opening 4140.

According to some embodiments, a width, W, of the opening 4140 isgreater than the spacing, S, of the first region 4120′ by a distanceequal to about half of the spacing, S. In other embodiments, the width,W, of the opening 4140 is greater than the spacing, S, by a distancegreater than half of the spacing, S. A height of the sidewalls 4122 ofthe first region 4120′ can be greater than about 50% of the height ofthe waveguide 4105. For example, a height of the sidewalls 4120 of thefirst region 4120′ can range between about 50% and 75% of the height ofthe optical waveguide 4105. In some embodiments, the height of thesidewalls 4122 of the first region 4120′ can be greater than about 62.5to 65 μm but less than a height of an optical waveguide 4105. In otherembodiments, the height of the sidewalls 4122 of the first region 4120′can be greater than about 75 μm but less than a height of an opticalwaveguide 4105. In the embodiment shown in FIG. 42, the overall heightof the Y-groove 4110 is about equal to the height of the waveguide 4105(e.g., about 125 μm). In some embodiments, the overall height of theY-groove 4110 can be less than or greater than the height of thewaveguide 4105. A cover 4135 (optional) may be configured to cover theoptical waveguides 4105 and grooves 4110 of the LCU 4100. As can be seenin FIG. 42, spacing between the sidewalls 4122 of the first region 4120′in a region of closest approach to the optical waveguide 4105 is largerthan the width of the waveguide by a predetermined clearance. In someembodiments, the predetermined clearance can be less than about 1 μm. Inother embodiments, the predetermined clearance can be between about 1and 3 μm. In further embodiments, the predetermined clearance can bebetween about 1 and 5 μm. For example, an optical waveguide 4105 canhave a width of about 125 μm, and the spacing separating the sidewalls4122 of the first region 4120′ can include a clearance of about 1 to 5μm.

In embodiments that employ a waveguide 4105 comprising multi-mode fiber,the predetermined clearance can be between about 1 and 5 μm. Forexample, the predetermined clearance can be equal to about 0.8 to 4% ofthe width of an optical waveguide 4105 that comprises multi-mode fiber.In embodiments that employ a waveguide 4105 comprising single modefiber, the predetermined clearance can be between about 0 and 2 μm. Forexample, the predetermined clearance can be equal to about 0 to 1.6% ofa width of an optical waveguide 4105 that comprises single mode fiber.In some cases, the clearance may be less than 0, so that the waveguide4105 deforms the Y-groove 4110 when placed in it (e.g., via aninterference fit).

The waveguide 4105 shown in FIGS. 42 and 43 includes a core 4107surrounded by cladding 4109. It is important that the core 4107 beoptically aligned with the light redirecting member (see 4104 in FIG.41) when the waveguide 4105 is permanently bonded in place within theY-groove 4110 using an optical (index-matched) bonding material. In someembodiments, the Y-groove 4110 includes a centering arrangement by whichthe waveguide 4105 is forcibly guided laterally toward a central plane4112 of the Y-groove 4110 when the waveguide 4105 is installed in theY-groove 4110. In addition to centering the core 4107 along a centralplane 4112 of the Y-groove 4110, the centering arrangement serves as astop that limits axial displacement of the waveguide 4105 within theY-groove 4110. As such, a compound Y-groove 4110 according to someembodiments includes a centering arrangement in combination with aU-groove alone or a Y-groove.

FIGS. 41 and 43 show a Y-groove 4110 that incorporates a centeringarrangement defined by a longitudinal transition section 4115 comprisinga first end 4115′ and a second end 4115″. The first end 4115′ has awidth equal to the spacing, S, between the sidewalls 4122 of the firstregion 4120′. The second end 4115″ has a width less than a width of theoptical waveguide 4105. The sidewall spacing progressively reduceswithin the transition section 4115, such as by the sidewalls anglinginwardly in the transition section 4115. The transition section 4115comprises centering sidewalls 4126 which can originate from terminalends of sidewalls 4122 and project inwardly toward the central plane ofthe Y-groove 4110. The centering sidewalls 4126 may be consideredchamfered sidewalls of the Y-groove 4110. The sidewalls 4122 andcentering sidewalls 4126 of the transition section 4115 can comprisesubstantially planar sidewall surfaces or non-planar sidewall surfaces.

The centering sidewalls 4126 form an angle, β, with the sidewalls 4122that can range between about 5 and 45 degrees. The longitudinaltransition section 4115 need not be very long relative to the overalllength of the Y-groove 4110. For example, length of the Y-groove 4110can be between 200 μm and 2000 μm, and the centering sidewalls 4126 canextend from the sidewalls 4122 by a distance of about 2 μm to 50 μm. Thecentering sidewalls 4126 can have the same height as that of thesidewalls 4122.

As the waveguide 4105 is displaced axially within the Y-groove 4110toward the light redirecting member 4104, the terminal end 4103 of thewaveguide 4105 contacts the centering sidewalls 4126 and is guidedtoward the central plane of the Y-groove 4110 so that the central axisof the waveguide 4105 is centered within the Y-groove 4110. A gap 4129is defined between terminal ends of the centering sidewalls 4126. Thegap 4129 is sufficiently wide to allow unimpeded passage of lightemanating from the core 4107 of the waveguide 4105. The length of thecentering sidewalls 4126 and width of the gap 4129 are preferably sizedto accommodate the core and cladding dimensions of the waveguide 4105.With the terminal end 4103 of the waveguide 4105 properly centeredwithin the Y-groove 4110 by the centering arrangement, the cladding 4109is in contact with the centering sidewalls 4126, and the core 4107 isaligned with the center of the gap 4129. It is understood that thecentering arrangement shown in FIG. 43 may be implemented in a U-groove,or in a compound U-groove such as a Y-groove.

FIG. 44 shows a top view of an LCU attachment area 4102 of an LCU 4100in accordance with various embodiments. The LCU attachment area 4102illustrated in FIG. 44 shows the terminal end 4103 of the waveguide 4105centered within the Y-groove 4110. The embodiment of the Y-groove 4110illustrated in FIG. 44 includes an alignment feature between theentrance 4111 and the longitudinal transition section 4115 of theY-groove 4110. The alignment feature includes a protruded section 4124of the groove sidewalls 4122. The spacing between opposing protrudedsections 4124 is slightly greater than the width of the waveguide 4105and less than the spacing between opposing sidewalls 4122. The protrudedsections 4124 of the alignment feature serve to provide angularalignment of the waveguide 4105 with respect to the central plane of theY-groove 4110 when the waveguide end 4103 is positioned in thetransition section 4115 of the Y-groove 4110. In some embodiments, thealignment feature formed by protruded sections 4124 is located at ornear the groove entrance 4111.

In the embodiment illustrated in FIG. 44, the edges of the terminal end4103 of the waveguide 4105 are shown slightly embedded in the centeringwalls 4126 of the transition section 4115. In this embodiment, thecladding 4109 of the waveguide 4105 is formed of a material (e.g.,glass) that is harder than the material used to form the centering walls4126. A deformation 4128 in the centering walls 4126 can be formed byapplying an axially directed force to the waveguide 4105 when theterminal end 4103 of the waveguide 4105 rests against the centeringwalls 4126 at its centered position. The deformation 4128 helps tomaintain proper centered positioning of the waveguide 4105 within theY-groove 4110 when optical bonding material is applied to permanentlybond the waveguide 4105 within the Y-groove 4110.

The embodiment of the Y-groove 4110 shown in FIG. 44 incorporates abonding region 4123 defined between the sidewalls 4122 of the Y-groove4110 and the outer periphery of the waveguide 4105. The bonding region4123 can be filled with bonding material (e.g., optical bondingmaterial) which, when cured, permanently bonds the waveguide 4105 withinthe Y-groove 4110. In some embodiments, the bonding region 4123 isdefined as a volume between the waveguide 4105, the planar bottomsurface 4125, and the sidewalls 4122. In other embodiments, a depressionor trough can be formed along a portion of the sidewalls 4122 where thebottom surface 4125 meets the sidewalls 4122 so as to increase thevolume of bonding material captured within the Y-groove 4110.

FIG. 44 also shows a forward adhesive cavity 4131 configured to receivea volume of optical bonding material which, when cured, serves toincrease the strength (e.g., integrity) of the bond between the terminalend 4103 of the waveguide 4105 and the LCU attachment area 4102. Theforward adhesive cavity 4131 can be configured to receive a volume ofmaterial other than an adhesive, such as an index gel or oil, forexample. In some embodiments, the adhesive cavity 4131 is configured totransmit light from an end of the waveguide 4105. As is shown in FIG.45, the forward adhesive cavity 4131 can include a depression 4131′formed into the bottom surface 4125 of the LCU attachment area 4102. Thedepression 4131′ serves to increase the total volume of the forwardadhesive cavity 4131 for receiving an optical bonding material, therebyenhancing the strength/integrity of the bond between the terminal end4103 of the waveguide 4105 and the LCU attachment area 4102. FIG. 45also shows the entrance 4111 of the Y-groove 4110 at a location 4133where the bottom surface 4125 of the groove 110 transitions from a slopeto a plateau.

FIG. 46 shows the bonding regions 4123 and forward adhesive cavity 4131illustrated in FIG. 44 and, in addition, shows a lateral adhesive cavity4121 extending laterally from each sidewall 4122 of the

Y-groove 4110. The lateral adhesive cavities 4121 can be extendedportions of the bonding regions 4123. The lateral adhesive cavities 4121provide a volume for receiving additional bonding material near thesides of the terminal end 103 of the waveguide 4105, which increases thestrength/integrity of the bond between the Y-groove 4110 and thewaveguide 4105. As is shown in FIG. 47, the lateral adhesive cavity 4121can include a depression 4121′ formed into the bottom surface 4125 ofthe LCU attachment area 4102. The depression 4121′ serves to increasethe total volume of the lateral adhesive cavity 4121 for receiving anoptical bonding material, thereby enhancing the strength/integrity ofthe bond between the waveguide 4105 and the Y-groove 4110. The lateraladhesive cavity 4121 can be configured to receive a volume of materialother than an adhesive, such as an index gel or oil, for example.

FIG. 48 illustrates an LCU attachment area 4102 comprising amultiplicity of grooves 4110 each having a waveguide 4105 disposedtherein. In FIG. 48, two grooves 4110 are illustrated with respectivewaveguides 4105 in contact with centering surfaces 4126 at a centeredposition within the grooves 4110. FIG. 48 shows an adhesive reservoir4131″ located adjacent the forward adhesive cavities 4131. The adhesivereservoir 4131″ is a volume of the LCU attachment area 4102 that isshared between two or more of the forward adhesive cavities 4131. Inthis regard, the adhesive reservoir 4131″ is fluidically coupled to twoor more of the forward adhesive cavities 4131. The adhesive reservoir4131″ provides a volume for receiving additional bonding material nearthe terminal ends 4103 of the waveguides 4105, which increases thestrength/integrity of the bond between the waveguide 4105 and the LCUattachment area 4102. The adhesive reservoir 4131″ can be configured toreceive a volume of material other than an adhesive, such as an indexgel or oil, for example.

FIGS. 49-55 illustrate a process for installing a waveguide 4105 in aY-groove 4110 of an LCU attachment area 4102 in accordance with variousembodiments. In some embodiments, the installation process can bemonitoring using microscopes with digital cameras to provide views(e.g., top view, side view) similar to those shown in FIGS. 49 and 50.The waveguide 4105 to be positioned within the Y-groove 4110 is shownextending from a buffer 4116 which encompasses the waveguide 4105. Thebuffer 4106 is typically a polymer sheath which serves to protect thewaveguide 4105.

The waveguide 4105 is initially positioned over the expanded region(i.e., upper region) of Y-groove 4110 with the terminal end 4103 pointeddownwards at a small angle (e.g., 5°-20°). FIGS. 49 and 50 illustrate atypical example in which the waveguide 4105 is initially misalignedwithin the Y-groove 4110. The upper expanded region of Y-groove 4110includes angled side surfaces 4132 which serve to capture the waveguide4105 and funnel the waveguide 4105 into the U-groove region (i.e., lowerregion) of the Y-groove 4110. As the terminal end 4103 of the waveguide4105 is lowered, the terminal end 4103 contacts the capturing sidewall4132 on one side of the Y-groove region, which guides the terminal end4103 into the bottom region (i.e., U-groove region) of the Y-groove4110, forcing the waveguide 4105 to bend and/or move laterally.

As the waveguide 4105 is lowered into the Y-groove 4110 (see FIG. 51),the terminal end 4103 is bent upward by the bottom surface 4125 of theY-groove 4110. Simultaneously, the Y-groove 4110 continues to bendand/or move the waveguide 4105 laterally so that the waveguide 4105 isconstrained by the near-vertical sidewalls 4122 of the U-groove regionof the Y-groove 4110 (see FIG. 52). When the waveguide 4105 isapproximately horizontal (i.e., tangent to the bottom surface 4125 ofthe Y-groove 4110), as is shown in FIG. 53, the waveguide 4105 is pushedforward into the longitudinal transition section 4115 of the Y-groove4110 (see FIG. 54) until the terminal end 4103 contacts a centeringsurface 4126 (see FIG. 55). The centering surface 4126 pushes theterminal end 4103 of the waveguide 4105 laterally as needed until theterminal end 4103 is in contact with the centering surfaces 4126 on bothsides of the Y-groove 4110, thereby precisely centering the terminal end4103 of the waveguide 4105 in the Y-groove 4110, as is best seen in FIG.55.

The final angle of the waveguide 4105 as it is centered by the centeringsurfaces 4126 is typically horizontal, and may be controlled by anysuitable mechanical means, optionally guided by optical inspection of aside view, such as the view shown in FIG. 53. FIG. 56 illustrates analignment error that can occur if the waveguide 4105 is lowered too muchsuch that it makes contact with the rear edge 4125′ of the bottomsurface 4125 of the Y-groove 4110. In this scenario, the terminal end4103 of the waveguide 4105 is levered up out of the Y-groove 4110. Thismisalignment is greatly reduced by recessing the most of the bottomsurface 4125 of the Y-groove 4110, leaving only a relatively short porchregion 4125″ (FIG. 57) at the terminal end 4113 of the Y-groove 4110.

As can be seen in FIG. 57, the majority of the bottom surface 4125′″ isrecessed relative to the porch region 4125″ adjacent the terminal end4113 of the Y-groove 4110. In some embodiments, the recessed section4125′″ of the bottom surface 4125 of the Y-groove 4110 can extend fromthe entrance 4111 of the Y-groove 4110 towards the terminal end 4113 andcover more than about one-half of the surface area of the bottom surface4125. For example, the recessed section 4125′″ can extend from theentrance 4111 of the Y-groove 4110 to within a distance from theterminal end 4113, the distance being less than about two times a heightof the waveguide 4105 received by the Y-groove 4110. Typically, at leasta portion of the recessed section 4125′″ will be filled with curedoptical adhesive, so that the waveguide 4105 is well supported.

A compound Y-groove 4110 comprising a lower U-groove and an expandedupper groove can be fabricated with injection molding of a thermoplastic(e.g., Ultem). Such materials have a much larger coefficient of thermalexpansion than that of glass optical fibers. Therefore, there is concernover stresses caused by thermal excursions, such as may occur inoperation in a computer chassis. These stresses may lead to opticalmisalignment due to warping of the part containing the Y-groove 4110, oreven to failure of the adhesive used to bond the waveguide 4105. Tominimize such stresses, it is desirable to minimize the length of theY-groove 4110 that is filled with adhesive. However, sufficient groovelength is required to constrain the angle of the waveguide 4105. Therequired length of the Y-groove 4110 depends on the angular tolerance ofthe optics system and on the extra width of the Y-groove 4110 includedto provide clearance for the waveguide 4105.

FIGS. 58-60 show a Y-groove 4110 with two separate sections 4110 a and4110 b. Near the terminal end 4103 of the waveguide 4105, a shortsection includes the longitudinal transition section 4115 and thecentering surfaces 4126. This section 4110 a may be filled withindex-matching adhesive. A separate section 4110 b is placed somesufficient distance (e.g., 0.5 mm) from the section 4110 b, such that itprovides accurate angular alignment of the waveguide 4105 but is notfilled with adhesive. This design minimizes stresses associated withthermal expansion (by minimizing the bond length) without compromisingangular alignment.

FIG. 61 illustrates a portion of an LCU 6100 in accordance with variousembodiments. The LCU 6100 shown in FIG. 61 includes a single LCUattachment area 6102. Although a single LCU attachment area 6102 isshown in FIG. 61, it is understood that a multiplicity of attachmentareas 6102 can be provided on the LCU 6100 for receiving and permanentlyattaching to a multiplicity of optical waveguides. The LCU attachmentarea 6102 includes a groove 6110 having an entrance 6111 and a terminalend 6113. The groove 6110 is configured to receive an optical waveguide,such as the generally cylindrical waveguide 4105 shown in FIG. 42.

The LCU 6100 includes a light redirecting member (not shown in FIG. 61,but see 4104 in FIG. 41) and an intermediate section 6108 between thelight redirecting member and the terminal end 6113. In some embodiments,the terminal end 6113 comprises an optically clear member, such as alens, or is formed from optically transparent material. The intermediatesection 6108 is formed from an optically transparent material. The lightredirecting member includes an output side through which light exitsfrom (or enters into) the light directing member.

According to some embodiments, the groove 6110 is a compound grooveformed by a generally U-shaped lower portion 6123 and an expanded upperportion 6127, 6132 making the compound groove generally Y-shaped(Y-groove), as has been described in detail hereinabove. The groove 6110includes a longitudinal transition section 6115 that includes a singlecentering sidewall 6126. Within the longitudinal transition section6115, the spacing between sidewalls 6122 and 6122′ reduces from a widthequal to that of the optical waveguide 6105 plus a clearance to a widthless than the width of the optical waveguide 6105. In the embodimentillustrated in FIG. 61, one of the sidewalls 6122 is substantiallyplanar between the entrance 6111 and terminal end 6113 of the groove6110. The opposing sidewall 6122′ includes a sidewall portion that issubstantially parallel to sidewall 6122 and transitions to the centeringsidewall 6126 that angles inwardly in the transition section 6115. Thecentering sidewall 6126 may be considered chamfered sidewall of thegroove 6110.

In FIG. 61, the groove 6110 includes a centering sidewall 6126 only onone side of the groove 6110. As such, the single centering sidewall 6126may be considered a positioning sidewall 6126. During assembly, theoptical waveguide 6105 is slid along the planar sidewall 6122 until thepositioning sidewall 6126 pins the optical waveguide 6105 at itsinstalled location within the groove 6110, as is shown in FIG. 61. Atthis location, the positioning sidewall 6126 prevents furtherlongitudinal advancement of the terminal end 6103 of the opticalwaveguide 6105 within the groove 6110. One advantage to the embodimentshown in FIG. 61 is that the angle of the optical waveguide 6105 can bewell controlled during assembly, since it can be bent parallel to thesidewall 6122. In some embodiments, the positioning sidewall 6126 neednot pinch the optical waveguide 6105, but can instead serve as aconventional stop, such as by defining the end of the groove 6110 orsome other barrier, as long as the optical waveguide 6105 can be bentagainst the sidewall 6122 during assembly.

FIG. 62 shows one side 6201 of an optical ferrule 6200, e.g., a moldedoptical ferrule, a molded plastic optical ferrule, that includesfiducials 1221-1224. Ferrule 6200 is configured to receive one or moreoptical waveguides and includes one or more features. Each featurecorresponds to a different optical waveguide. The ferrule 6200 alsoincludes one or more fiducials, wherein the one or more fiducialscorrespond to the one or more features. According to someimplementation, the features of the optical ferrule 6200 are opticalelements configured to be on an optical path of a light ray propagatingwithin the ferrule and the one or more fiducials correspond to the oneor more optical elements.

The ferrule 6200 includes elements 6203, e.g., grooves, U-shaped,V-shaped, or Y-shaped grooves configured for receiving and securing anoptical waveguide. Ferrule 6200 includes one or more light affectingelements 6205 configured for affecting characteristics of light from theoptical waveguide while propagating the light within the optical ferrule6200. According to some embodiments, each light affecting element 6205of the ferrule 6200 comprises a light redirecting feature 6205 a thatmay include a curved lens 6206 and a planar surface 6207 disposedproximate to and/or at least partially surrounding the lens 6206. Thelight affecting element 6205 further includes an intermediate surface6205 b, e.g., a planar surface, disposed between the receiving element6203 and light redirecting feature 6205 a. Optical ferrule 6200 includesmultiple receiving and securing elements 6203 and multiple lightaffecting elements 6205, however, some unitary optical ferrules caninclude a single receiving and securing element and a single lightaffecting element with an intermediate surface disposed therebetween.

The optical ferrule includes one or more alignment features, includingfeature 6211 configured to control translation of the ferrule 6200 alonga first lateral axis 121. Features 6211 shown in the example opticalferrule 6200 are forward stops that engage with forward stops of amating ferrule to set the mated distance between light affectingelements of the optical ferrule and light affecting elements of themating ferrule. The forward stops 6211, when engaged with forward stopsof the mating ferrule, also control rotation of the optical ferrule 6200around the thickness axis 123.

The optical ferrule 6200 includes alignment features 6212, 6213 whereinalignment feature 6212 is a pin that fits into a compatible socket of amating ferrule. Alignment feature 6213 is a socket that fits a pin ofthe mating ferrule. The pin 6212 includes spaced apart portions 6212 aand 6212 b. The pin 6212 and socket 6213 control translation of theoptical ferrule 6200 along the second lateral axis 622 and may alsocontrol rotation of the optical ferrule 6200 around the thickness axis623. Pin 6212 may be designed such that only the sides of the pin 6212can come into contact with the mating socket, providing a lateral stopon either side of the pin 6212 and thereby controlling translation alongthe second lateral axis 122. The pin 6212 is designed to be slightlynarrower that the socket 6213 to allow for manufacturing tolerances.Optionally, compliant features (not shown) could be designed into thepin and/or socket to allow for manufacturing tolerances. In someembodiments, the compliant features may provide flexible alignment. Thepin or the socket, or both, can be fitted with compliant side featuresthat facilitate centering the pin in the socket.

Additional information regarding optical ferrules having alignmentfeatures is provided in commonly owned and concurrently filed U.S.Patent Application S/N 62/240,069, having the title “Optical Ferrules”and identified by Attorney Docket Number 76982US002 which isincorporated herein by reference. Additional information regardingoptical ferrules, frames, and connectors that employ flexible alignmentfeatures is proivded in commonly owned and concurrently filed U.S.Patent Application S/N 62/240,066, having the title “Ferrules, AlignmentFrames and Connectors” and identified by Attorney Docket Number75767US002 which is incorporated herein by reference.

The planar mating surface 6217 of optical ferrule 6200 controlstranslation of the ferrule 6200 along the thickness axis 123 androtation of the ferrule 6200 along the first and second lateral axes121, 122. An optical output window 6214 is disposed, e.g., recessed, inthe planar mating surface 6217.

Optical ferrules and the molds used to make the optical ferrulesaccording to various embodiments, including those illustrated herein,involve molded features, e.g., plastic molded features, configured toprovide for propagation of light within the ferrule and between theferrule and a mating ferrule that is aligned with the ferrule. Forexample, the light affecting elements may comprise lenses, e.g., curvedlenses, configured to redirect light propagating in the ferrule. Aspreviously described, the optical ferrules can include a planar matingsurface having optical output window that is transparent to thepropagating light, wherein the light propagating in the optical ferruleexits the optical ferrule after being transmitted by the optical outputwindow.

In some embodiments, one or more fiducials may be molded into theferrule wherein the fiducials correspond to the ferrule features. Forexample, a mold side may be fabricated by one or more tools and eachfiducial may be a divot (or other feature) that indicates a location ofthe tool used form a mold feature.

One fiducial may correspond to a plurality of ferrule features or onefiducial may correspond to a single ferrule feature. For example, inimplementations that include multiple light affecting elements, multiplefiducials may be used wherein each of the fiducials corresponds to oneof the light affecting elements. In some embodiments, as shown in FIG.62, two or more fiducials 6221, 6222 may correspond to a lightredirecting feature 6205 a, e.g., each light redirecting feature 6205 amay be disposed between two fiducials 6221, 6222.

According to some implementations, at least one fiducial may correspondto at least a single receiving element. In implementations that includemultiple receiving elements, multiple fiducials may be used, whereineach of the fiducials corresponds to one of the receiving elements. Forexample, as shown in FIG. 62, two or more fiducials 6223, 6224 maycorrespond to one of the receiving elements 6203, e.g., each receivingelement 6203 may be disposed between two fiducials 6223, 6224. Fiducialsthat correspond to one feature (or type of feature) may have the sameshape or may differ in shape from fiducials that correspond to anotherfeature (or type of feature).

Additional information regarding ferrules, alignment frames, andconnectors that may be used in conjunction with the approaches describedherein is provided in the following commonly owned and concurrentlyfiled U.S. Patent Applications which are incorporated herein byreference: U.S. Patent Application S/N 62/239,998, having the title“Connector with Latching Mechanism” and identified by Attorney DocketNumber 76663US002; U.S. Patent Application S/N 62/240,069, having thetitle “Optical Ferrules” and identified by Attorney Docket Number76982US002; U.S. Patent Application S/N 62/240,066, having the title“Ferrules, Alignment Frames and Connectors,” and identified by AttorneyDocket Number 75767US002; U.S. Patent Application S/N 62/240,010, havingthe title “Optical Coupling Device with Waveguide AssistedRegistration,” identified by Attorney Docket Number 76660US002; U.S.Patent Application S/N 62/240,000, having the title “Dust MitigatingOptical Connector,” identified by Attorney Docket Number 76664US002;U.S. Patent Application S/N 62/240,009, having the title “OpticalWaveguide Registration Feature,” identified by Attorney Docket Number76661US002; U.S. Patent Application 62/239,996, having the title“Optical Ferrules and Optical Ferrule Molds,” identified by AttorneyDocket Number 75985US002; U.S. Patent Application 62/240,002, having thetitle “Optical Ferrules with Waveguide Inaccessible Space,” identifiedby Attorney Docket Number 76778US002; U.S. Patent Application62/104,196, having the title “Configurable Modular Connectors,”identified by Attorney Docket Number 75907US002; and U.S. PatentApplication 62/240,005, having the title “Hybrid Connectors,” identifiedby Attorney Docket Number 76908US002.

-   Items described in this disclosure include:-   Item 1. An optical cable subassembly comprising:

one or more optical waveguides;

at least one light coupling unit comprising a first attachment areapermanently attached to the optical waveguides; and

at least one cable retainer comprising a second attachment areapermanently attached to the optical waveguides and adapted to beinstalled in a housing, a length of the optical waveguides between thefirst attachment area and the second attachment area configured to allowa bend in the optical waveguides that provides a predetermined matingspring force at a predetermined angle of the light coupling unit wheninstalled in the housing.

-   Item 2. The subassembly of item 1, wherein the optical cable    subassembly is adapted to be installed in and subsequently removed    from the housing without damage to the housing or optical cable    subassembly.-   Item 3. The subassembly of any of items 1 through 2, wherein:

the one or more optical waveguides comprises multiple waveguide arrays;and

the at least one cable retainer comprises a single cable retainerattached to each of the multiple waveguide arrays.

-   Item 4. The subassembly of any of items 1 through 3, wherein the    cable retainer is adhesively attached to the optical waveguides.-   Item 5. The subassembly of any of items 1 through 4, wherein the    cable retainer is attached to the optical waveguides by one or more    mechanical fasteners.-   Item 6. The subassembly of any of items 1 through 5, wherein the    cable retainer is attached to cladding of the optical waveguides.-   Item 7. The subassembly of any of items 1 through 6, wherein the    cable retainer is attached to buffer coatings of the optical    waveguides.-   Item 8. The subassembly of any of items 1 through 7, wherein the    cable retainer is attached to a jacket of the plurality of optical    waveguides.-   Item 9. The subassembly of any of items 1 through 8, wherein    adhesive is disposed between an outer surface of the plurality of    optical waveguides and an inner surface of the cable retainer.-   Item 10. The subassembly of any of items 1 through 9, wherein the    cable retainer includes features that provide a space for adhesive    between the inner surface of the cable retainer and the outer    surface of the plurality of optical waveguides.-   Item 11. The subassembly of any of items 1 through 10, wherein the    cable retainer includes fingers configured to grip the plurality of    optical waveguides in response to a force applied to the fingers.-   Item 12. The subassembly of any of items 1 through 10, wherein the    cable retainer is a unitary component.-   Item 13. The subassembly of any of items 1 through 10, wherein the    cable retainer is a multi-piece component.-   Item 14. The subassembly of any of items 1 through 10, wherein the    cable retainer includes first and second pieces and the optical    waveguides are disposed between the first and second pieces.-   Item 15. The subassembly of any of items 1 through 10, wherein the    cable retainer includes a channel piece and a plate piece and the    optical waveguides are disposed between the channel piece and the    plate piece.-   Item 16. The subassembly of any of items 1 through 10, wherein the    cable retainer includes a first channel piece and a second channel    piece and the optical waveguides are disposed between the first    channel piece and the second channel piece.-   Item 17. The subassembly of any if items 1 through 10, wherein the    cable retainer includes a first piece and a second piece that fits    at least partially within the first piece and the optical waveguides    are attached to the cable retainer between the first piece and the    second piece.-   Item 18. The subassembly of any of items 1 through 10, further    comprising an elastomeric grommet that is compressed around the    optical waveguides when the optical waveguides are disposed within    the cable retainer.-   Item 19. The subassembly of any of items 1 through 10, wherein the    cable retainer includes a first piece and a second piece attached to    the first piece by a hinge.-   Item 20. The subassembly of any of items 1 through 10, wherein the    cable retainer includes a first piece and a second piece with the    optical waveguides disposed between the first piece and the second    piece, the first piece and the second piece including complementary    latching parts that latch the first piece and the second piece    together.-   Item 21. The subassembly of any of items 1 through 10, wherein the    cable retainer comprises a key configured to orient the cable    retainer within the housing.-   Item 22. The subassembly of any of items 1 through 21, wherein an    inner surface of the cable retainer includes alignment grooves, each    alignment groove dimensioned to receive an optical waveguide of the    one or more optical waveguides.-   Item 23. The subassembly of any of items 1 through 22, wherein the    cable retainer has a first end and a second end and the retainer has    a beveled opening at one or both of the first end and the second    end.-   Item 24. The subassembly of any of items 1 through 23, wherein the    cable retainer has a first end having a first opening for the    optical waveguides and a second end with a second opening for the    optical waveguides and the optical waveguides bend inside the cable    retainer between the first end and the second end.-   Item 25. The subassembly of any of items 1 through 24, wherein the    cable retainer has a first end with a first opening for the optical    waveguides and a second end with a second opening for the optical    waveguides and the optical waveguides are not perpendicular to a    major surface of at least one end of the cable retainer.-   Item 26. The subassembly of any of items 1 through 25, further    comprising a strain relief boot, wherein the cable retainer is    disposed between the boot and the light coupling unit.-   Item 27. The subassembly of any of items 1 through 26, wherein the    cable retainer includes a strain relief section attached to a jacket    of the plurality of optical waveguides.-   Item 28. The subassembly of item 27, wherein the cable retainer is    attached to a cladding of the optical waveguides of the plurality of    optical waveguides.-   Item 29. The subassembly of item 27, wherein the cable retainer is    attached to a buffer coating of the optical waveguides of the    plurality of optical waveguides.-   Item 30. The subassembly of item 27, wherein the cable retainer is    attached to a jacket of the plurality of optical waveguides.-   Item 31. The subassembly of any of items 1 through 30, wherein first    attachment area comprises one or more grooves provided at the    attachment area, each groove configured to receive an optical    waveguide and defined by:

a first region, a second region, an opening, and a bottom surface;

the first region defined between the bottom surface and the secondregion, the first region in cross section having substantially parallelsidewalls separated by a spacing; and

the second region disposed between the first region and the opening,wherein a width of the opening is greater than the spacing.

-   Item 32. The subassembly of any of items 1 through 31, wherein the    first attachment area comprises:

one or more grooves, each groove configured to receive an opticalwaveguide having a width;

each groove having a first region and a bottom surface, the first regionin cross section having substantially parallel sidewalls separated by aspacing; and

each groove having a longitudinal transition section comprising a firstend and a second end, the first end having a sidewall spacing greaterthan the width of the optical waveguide, and the second end having asidewall spacing less than the width of the optical waveguide.

-   Item 33. The subassembly of any of items 1 through 32, wherein the    first attachment area comprises:

a one or more grooves, each groove configured to receive an opticalwaveguide having a width;

each groove having a first region and a bottom surface, the first regionin cross section having substantially parallel sidewalls separated by aspacing; and

each groove having two or more sections along a longitudinal directionwherein each section has a different sidewall spacing than adjoiningsections, wherein at least one of the sections has a sidewall spacingless than a width of the optical waveguide.

-   Item 34. The subassembly of any of items 1 through 33, wherein the    light coupling unit comprises:

a first major surface comprising one or more substantially parallelfirst grooves oriented along a first direction for receiving one or moreoptical waveguides; and

a second major surface for slidably contacting a mating light couplingunit, the second major surface comprising: an optically transmittingwindow for propagating an optical signal therethrough; and a region ofsecond grooves and lands configured to capture particulate contaminantsin the second grooves.

-   Item 35. The subassembly of any of items 1 through 34, wherein the    light coupling unit comprises:

a first major surface comprising one or more substantially parallelfirst grooves oriented along a first direction for receiving one or moreoptical waveguides; and

a second major surface for slidably contacting a mating light couplingunit, the second major surface comprising:

-   -   an optically transmitting window for propagating an optical        signal therethrough; and    -   a region of second grooves and lands configured to capture        particulate contaminants in the second grooves, the second        grooves substantially parallel to each other and oriented along        a direction different from the first direction of the first        grooves on the first major surface.

-   Item 36. The subassembly of any of items 1 through 35, wherein the    light coupling unit comprises;

an optically transmitting window for propagating an optical signaltherethrough;

a plurality of substantially parallel first grooves on a first region ofthe surface oriented along a first direction; and

a plurality of substantially parallel second grooves on a second regionof the surface oriented along the first direction; and

a third region of the first major surface disposed between first andsecond regions, the third region being substantially devoid of grooves.

-   Item 37. The subassembly of any of items 1 through 36, wherein:

the first attachment area comprises a plurality of first grooves; and

the light coupling unit is adapted to mate with a mating light couplingunit along a mating direction, the light coupling unit comprising aplurality of substantially parallel second grooves in a mating surfaceoriented along a first direction different than the mating direction.

-   Item 38. The subassembly of any of items 1 through 37, wherein the    light coupling unit comprises:

a first section comprising a mating tongue having a mating tonguesurface;

a second section comprising:

-   -   a first surface comprising the first attachment area configured        for receiving and permanently attaching to the optical        waveguides; and    -   a second mating surface opposing the first surface and        comprising a plurality of grooves, the grooves configured to        capture particulate contaminants between the second mating        surface and a mating tongue surface of a mating light coupling        unit;    -   a plurality of light redirecting members on the first surface        optically coupled to the optical waveguides; and    -   an optically transmitting window on the second mating surface        between the grooves and the mating tongue, the optically        transmitting window optically coupled to the light redirecting        members.

-   Item 39. The subassembly of any of item 1 through 38, wherein the    light coupling unit includes one or more curved surfaces, each    curved surface corresponding to a different optical waveguide, the    curved surface being configured to change a divergence of light from    the optical waveguide.

-   Item 40. An optical cable subassembly comprising:

one or more optical waveguides;

at least one light coupling unit permanently attached to and adapted toreceive optical signals from the optical waveguides and propagate thereceived optical signal therein; and

a cable retainer permanently attached to the plurality of opticalwaveguides and adapted to engage a corresponding retainer mount in aconnector housing such than when the subassembly is installed in thehousing, the engagement of the cable retainer and the retainer mountprovides the only attachment of the subassembly to the housing betweenthe cable retainer and the light coupling unit.

-   Item 41. An optical cable subassembly comprising:

one or more optical waveguides;

at least one light coupling unit comprising a first attachment area forreceiving and permanently attaching to the plurality of opticalwaveguides; and

at least one cable retainer comprising a second attachment area forreceiving and attaching to the optical waveguides, the cable retainerdimensioned to couple with a retainer mount of a connector housing suchthat a position of the second attachment area within the connectorhousing is fixed, the light coupling unit and the first attachment areaconfigured to move within the connector housing relative to the fixedposition of the second attachment area, and a length of the opticalwaveguides between the first attachment area and the second attachmentarea allows the optical waveguides to bend within the housing as thefirst attachment area moves relative to the second attachment area.

-   Item 42. The subassembly of item 41, wherein:

the retainer mount comprises a slot, and

the cable retainer is configured to grip and attach to the opticalwaveguides due to friction between outer surfaces of the opticalwaveguides and inner surfaces of the cable retainer due to a forceapplied by the slot on the cable retainer.

-   Item 43. The subassembly of any of items 41 through 42, wherein the    cable retainer is cylindrical in shape, and has a key to control the    rotary position of the cable retainer in the housing, thereby    controlling an angle of the optical waveguides.-   Item 44. An optical cable subassembly comprising:

one or more optical waveguides;

at least one light coupling unit comprising a first attachment area forreceiving and permanently attaching to the plurality of opticalwaveguides; and

at least one cable retainer comprising a second attachment area forreceiving and attaching to the plurality of optical waveguides, thecable retainer dimensioned to couple with a retainer mount of aconnector housing such that a position of the second attachment areawithin the connector housing is fixed, a length of the plurality ofoptical waveguides between the first attachment area and the secondattachment area of the optical cable subassembly being greater than astraight-line distance between the first attachment area and the secondattachment area after the optical cable subassembly is installed in theconnector housing.

-   Item 45. An optical connector housing comprising:

a mating end;

a non-mating end opposite the mating end; and

a passageway extending between the mating end and the non-mating end,the passageway dimensioned to receive an optical cable subassemblyincluding one or more optical waveguides attached to at least one lightcoupling unit and to at least one cable retainer;

a retainer mount configured to receive the cable retainer in the housingsuch that the position of the optical cable subassembly is fixed withinthe housing by the retainer mount, the passageway dimensioned toconstrain the optical waveguides to bend within the housing between theretainer mount and the mating end.

-   Item 46. The housing of item 45, wherein sides of the passageway are    curved.-   Item 47. The housing of any of items 45 through 46, wherein sides of    the passageway are configured to support the optical cable    subassembly within the housing when the light coupling unit is in an    unmated position.-   Item 48. The housing of any of items 45 through 47, further    comprising features configured to support the light coupling unit    when the light coupling unit is in an unmated position.-   Item 49. The housing of any of items 45 through 48, further    comprising a feature at a mating end of the housing configured to    support the optical waveguides near the light coupling unit when the    light coupling unit is in an unmated position.-   Item 50. The housing of any of items 45 through 49, wherein arms    extending at a mating end of the housing are configured to support    the light coupling unit.-   Item 51. The housing of any of items 45 through 50, wherein the    retainer mount is a slot.-   Item 52. The housing of any of items 45 through 51, wherein the    cable retainer comprises one or more holes in the cable retainer and    the retainer mount comprises one or more pegs that fit within the    holes.-   Item 53. The housing of any of items 45 through 52, wherein the    cable retainer comprises one or more pegs and the retainer mount of    the housing comprises one or more holes, each hole dimensioned to    receive the one of the pegs.-   Item 54. The housing of any of items 45 through 53, wherein the    cable retainer includes a key configured to control rotary    orientation of the cable retainer in the retainer mount.-   Item 55. An optical connector assembly comprising:

an optical cable subassembly comprising:

-   -   one or more optical waveguides;    -   at least one light coupling unit comprising a first attachment        area for receiving and permanently attaching to the optical        waveguides; and    -   at least one cable retainer comprising a second attachment area        for receiving and attaching to the optical waveguides; and

a housing comprising:

-   -   at least one passageway dimensioned to receive the optical cable        subassembly; and    -   at least one retainer mount configured to couple with the cable        retainer such that a position of second attachment area is fixed        within the housing, the passageway dimensioned to constrain the        optical waveguides to bend within the housing between the first        attachment area and the second attachment area.

-   Item 56. The assembly of item 55, wherein a longitudinal axis of the    optical waveguides within the cable retainer is angled with respect    to a mating direction of the connector housing.

-   Item 57. The assembly of any of items 55 and 56, wherein the cable    retainer has a first end with a first opening for the optical    waveguides and a second end with a second opening for the optical    waveguides and the cable retainer has a longitudinal axis between    the first opening and the second opening and the longitudinal axis    of the cable retainer is substantially parallel to a mating    direction of the connector housing.

-   Item 58. The assembly of any of items 55 through 56, wherein the    cable retainer has a first end with a first opening for the optical    waveguides and a second end with a second opening for the optical    waveguides and the cable retainer has a longitudinal axis between    the first opening and the second opening and the longitudinal axis    of the cable retainer is angled with respect to a mating direction    of the connector housing.

-   Item 59. The assembly of any of items 55 through 58, wherein the    cable retainer is disposed entirely within the connector housing.

-   Item 60. The assembly of any of items 55 through 58, wherein the    cable retainer is disposed partially within the connector housing    and partially outside the connector housing.

-   Item 61. A method of making an optical cable subassembly comprising:

attaching one or more optical waveguides at a first attachment area of alight coupling unit, the first attachment area configured for receivingand permanently attaching to the optical waveguides; and

attaching the optical waveguides to a cable retainer comprising a secondattachment area for receiving and attaching to the optical waveguides, alength of the optical waveguides between the first attachment area andthe second attachment area configured to allow a bend in the opticalwaveguides that provides a predetermined mating spring force at apredetermined angle of the light coupling unit.

-   Item 62. The method of item 61, wherein attaching the optical    waveguides to the cable retainer comprises inserting a linear array    of waveguides into a channel of the cable retainer by motion    primarily along a direction parallel to a plane of the array of    waveguides, and orthogonal to a direction of axes of the waveguides.-   Item 63. The method of item 61, wherein attaching the optical    waveguides to the cable retainer comprises inserting a linear array    of waveguides into a channel of the cable retainer by motion    primarily along a direction perpendicular to the plane of the array    of waveguides, and orthogonal to the direction of the waveguide    axes.-   Item 64. The method of item 61, wherein attaching the plurality of    optical waveguides to the cable retainer comprises threading a    linear array of waveguides through a closed channel of the cable    retainer.-   Item 65. The method of any of items 61 through 64, further    comprising attaching a strain relief boot over the optical waveguide    on the opposite side of the cable retainer from the light coupling    unit.-   Item 66. The method of item 65, wherein the strain relief boot is    attached to the cable retainer before the cable retainer is    assembled into the housing.-   Item 67. A method of making an optical connector assembly    comprising:

assembling an optical cable subassembly comprising:

-   -   attaching one or more optical waveguides at a first attachment        area of a light coupling unit;    -   attaching the optical waveguides at a second attachment area of        a cable retainer; inserting the optical cable subassembly into a        housing comprising:    -   coupling the cable retainer to a retainer mount in the housing,        the coupling of the cable retainer into the retainer mount        fixing a position of the optical cable assembly within the        housing; and    -   inserting the optical waveguides into a passageway in the        housing, the passageway dimensioned to constrain the optical        waveguides to bend within the housing between the first        attachment area and the second attachment area.

-   Item 68. A method of making an optical connector assembly    comprising:

assembling an optical cable subassembly comprising:

attaching one or more optical waveguides at a first attachment area of alight coupling unit;

attaching the optical waveguides at a second attachment area of a cableretainer;

inserting the optical cable subassembly into a housing comprising:

coupling the cable retainer to a retainer mount in the housing, thecoupling of the retainer and the retainer mount fixing a position of theoptical cable assembly within the housing; and

inserting the optical waveguides into a passageway within the housing, alength of the optical waveguides between the first attachment area andthe second attachment area being greater than a distance between thefirst attachment area and the second attachment area after the opticalcable subassembly is installed in the connector housing.

-   Item 69. An optical ferrule comprising one or more optical elements,    each optical element configured to be on an optical path of a light    ray propagating within the ferrule, and one or more fiducials, the    one or more fiducials corresponding to the one or more optical    elements.-   Item 70. The optical ferrule of item 69, wherein the one or more    optical elements comprise a plurality of optical elements and each    fiducial corresponds to one of the optical elements.-   Item 71. The optical ferrule of any of item 69 through 70 wherein    multiple fiducials correspond to each of the optical elements.-   Item 72. The optical ferrule of item 71, wherein the multiple    fiducials comprise at least two fiducials.-   Item 73. The optical ferrule of item 72, wherein the optical element    is disposed between the two fiducials.-   Item 74. An optical ferrule configured to receive a one or more    optical waveguides and comprising: one or more features, each    feature corresponding to a different optical waveguide; and one or    more fiducials, the one or more fiducials corresponding to the one    or more features.-   Item 75. The optical ferrule of item 74, wherein the one or more    features comprise one or more elements configured for receiving and    securing the optical waveguides.-   Item 76. The optical ferrule of item 75, wherein the elements    configured for receiving and securing the optical waveguides    comprise grooves.-   Item 77. The optical ferrule of any of items 74 through 76, wherein    the one or more features comprise one or more light redirecting    features.-   Item 78. The optical ferrule of any of items 74 through 77 wherein    one fiducial corresponds to multiple features.-   Item 79. The optical ferrule of any of items 74 through 78, wherein    multiple fiducials correspond to each feature.-   Item 80. The optical ferrule of item 79, wherein the multiple    fiducials comprise at least two fiducials.-   Item 81. The optical ferrule of itsm 80, wherein the each feature is    disposed between the at least two fiducials.

Unless otherwise indicated, all numbers expressing feature sizes,amounts, and physical properties used in the specification and claimsare to be understood as being modified in all instances by the term“about.” Accordingly, unless indicated to the contrary, the numericalparameters set forth in the foregoing specification and attached claimsare approximations that can vary depending upon the desired propertiessought to be obtained by those skilled in the art utilizing theteachings disclosed herein. The use of numerical ranges by endpointsincludes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2,2.75, 3, 3.80, 4, and 5) and any range within that range.

Various modifications and alterations of the embodiments discussed abovewill be apparent to those skilled in the art, and it should beunderstood that this disclosure is not limited to the illustrativeembodiments set forth herein. The reader should assume that features ofone disclosed embodiment can also be applied to all other disclosedembodiments unless otherwise indicated. It should also be understoodthat all U.S. patents, patent applications, patent applicationpublications, and other patent and non-patent documents referred toherein are incorporated by reference, to the extent they do notcontradict the foregoing disclosure.

1-15. (canceled)
 16. An optical cable subassembly comprising: one ormore optical waveguides; at least one light coupling unit comprising afirst attachment area permanently attached to the optical waveguides;and at least one cable retainer comprising a second attachment areapermanently attached to the optical waveguides and adapted to beinstalled in a housing, a length of the optical waveguides between thefirst attachment area and the second attachment area configured to allowa bend in the optical waveguides that provides a predetermined matingspring force at a predetermined angle of the light coupling unit wheninstalled in the housing.
 17. The subassembly of claim 16, wherein theoptical cable subassembly is adapted to be installed in and subsequentlyremoved from the housing without damage to the housing or optical cablesubassembly.
 18. The subassembly of claim 16, wherein: the one or moreoptical waveguides comprises multiple waveguide arrays; and the at leastone cable retainer comprises a single cable retainer attached to each ofthe multiple waveguide arrays.
 19. The subassembly of claim 16, whereinadhesive is disposed between an outer surface of the plurality ofoptical waveguides and an inner surface of the cable retainer.
 20. Thesubassembly of claim 16, wherein the cable retainer includes featuresthat provide a space for adhesive between the inner surface of the cableretainer and the outer surface of the plurality of optical waveguides.21. The subassembly of claim 16, wherein the cable retainer is a unitarycomponent.
 22. The subassembly of claim 16, wherein the cable retainerincludes first and second pieces and the optical waveguides are disposedbetween the first and second pieces.
 23. The subassembly of claim 16,wherein the cable retainer includes a first channel piece and a secondchannel piece and the optical waveguides are disposed between the firstchannel piece and the second channel piece.
 24. The subassembly of claim16, wherein the cable retainer includes a first piece and a second piecethat fits at least partially within the first piece and the opticalwaveguides are attached to the cable retainer between the first pieceand the second piece.
 25. The subassembly of claim 16, wherein the cableretainer includes a first piece and a second piece attached to the firstpiece by a hinge.
 26. The subassembly of claim 16, wherein the cableretainer includes a first piece and a second piece with the opticalwaveguides disposed between the first piece and the second piece, thefirst piece and the second piece including complementary latching partsthat latch the first piece and the second piece together.
 27. Thesubassembly of claim 16, wherein the cable retainer has a first endhaving a first opening for the optical waveguides and a second end witha second opening for the optical waveguides and the optical waveguidesbend inside the cable retainer between the first end and the second end.28. The subassembly of claim 16, wherein the cable retainer has a firstend with a first opening for the optical waveguides and a second endwith a second opening for the optical waveguides and the opticalwaveguides are not perpendicular to a major surface of at least one endof the cable retainer.
 29. The subassembly of claim 16, wherein firstattachment area comprises one or more grooves provided at the attachmentarea, each groove configured to receive an optical waveguide and definedby: a first region, a second region, an opening, and a bottom surface;the first region defined between the bottom surface and the secondregion, the first region in cross section having substantially parallelsidewalls separated by a spacing; and the second region disposed betweenthe first region and the opening, wherein a width of the opening isgreater than the spacing.
 30. The subassembly of claim 16, wherein thefirst attachment area comprises: one or more grooves, each grooveconfigured to receive an optical waveguide having a width; each groovehaving a first region and a bottom surface, the first region in crosssection having substantially parallel sidewalls separated by a spacing;and each groove having a longitudinal transition section comprising afirst end and a second end, the first end having a sidewall spacinggreater than the width of the optical waveguide, and the second endhaving a sidewall spacing less than the width of the optical waveguide.31. The subassembly of claim 16, wherein the first attachment areacomprises: a one or more grooves, each groove configured to receive anoptical waveguide having a width; each groove having a first region anda bottom surface, the first region in cross section having substantiallyparallel sidewalls separated by a spacing; and each groove having two ormore sections along a longitudinal direction wherein each section has adifferent sidewall spacing than adjoining sections, wherein at least oneof the sections has a sidewall spacing less than a width of the opticalwaveguide.
 32. The subassembly of claim 16, wherein the light couplingunit comprises: a first major surface comprising one or moresubstantially parallel first grooves oriented along a first directionfor receiving one or more optical waveguides; and a second major surfacefor slidably contacting a mating light coupling unit, the second majorsurface comprising: an optically transmitting window for propagating anoptical signal therethrough; and a region of second grooves and landsconfigured to capture particulate contaminants in the second grooves.33. The subassembly of claim 16, wherein the light coupling unitcomprises: a first major surface comprising one or more substantiallyparallel first grooves oriented along a first direction for receivingone or more optical waveguides; and a second major surface for slidablycontacting a mating light coupling unit, the second major surfacecomprising: an optically transmitting window for propagating an opticalsignal therethrough; and a region of second grooves and lands configuredto capture particulate contaminants in the second grooves, the secondgrooves substantially parallel to each other and oriented along adirection different from the first direction of the first grooves on thefirst major surface.
 34. The subassembly of claim 16, wherein the lightcoupling unit comprises; an optically transmitting window forpropagating an optical signal therethrough; a plurality of substantiallyparallel first grooves on a first region of the surface oriented along afirst direction; and a plurality of substantially parallel secondgrooves on a second region of the surface oriented along the firstdirection; and a third region of the first major surface disposedbetween first and second regions, the third region being substantiallydevoid of grooves.
 35. The subassembly of claim 16, wherein: the firstattachment area comprises a plurality of first grooves; and the lightcoupling unit is adapted to mate with a mating light coupling unit alonga mating direction, the light coupling unit comprising a plurality ofsubstantially parallel second grooves in a mating surface oriented alonga first direction different than the mating direction.
 36. Thesubassembly of claim 16, wherein the light coupling unit comprises: afirst section comprising a mating tongue having a mating tongue surface;a second section comprising: a first surface comprising the firstattachment area configured for receiving and permanently attaching tothe optical waveguides; and a second mating surface opposing the firstsurface and comprising a plurality of grooves, the grooves configured tocapture particulate contaminants between the second mating surface and amating tongue surface of a mating light coupling unit; a plurality oflight redirecting members on the first surface optically coupled to theoptical waveguides; and an optically transmitting window on the secondmating surface between the grooves and the mating tongue, the opticallytransmitting window optically coupled to the light redirecting members.37. The subassembly of claim 16, wherein the light coupling unitincludes one or more curved surfaces, each curved surface correspondingto a different optical waveguide, the curved surface being configured tochange a divergence of light from the optical waveguide.
 38. An opticalcable subassembly comprising: one or more optical waveguides; at leastone light coupling unit permanently attached to and adapted to receiveoptical signals from the optical waveguides and propagate the receivedoptical signal therein; and a cable retainer permanently attached to theplurality of optical waveguides and adapted to engage a correspondingretainer mount in a connector housing such than when the subassembly isinstalled in the housing, the engagement of the cable retainer and theretainer mount provides the only attachment of the subassembly to thehousing between the cable retainer and the light coupling unit.
 39. Anoptical cable subassembly comprising: one or more optical waveguides; atleast one light coupling unit comprising a first attachment area forreceiving and permanently attaching to the plurality of opticalwaveguides; and at least one cable retainer comprising a secondattachment area for receiving and attaching to the optical waveguides,the cable retainer dimensioned to couple with a retainer mount of aconnector housing such that a position of the second attachment areawithin the connector housing is fixed, the light coupling unit and thefirst attachment area configured to move within the connector housingrelative to the fixed position of the second attachment area, and alength of the optical waveguides between the first attachment area andthe second attachment area allows the optical waveguides to bend withinthe housing as the first attachment area moves relative to the secondattachment area.